diff --git a/src/activity_handlers.cpp b/src/activity_handlers.cpp
index 0a3441b356e0..80ef07a576b7 100644
--- a/src/activity_handlers.cpp
+++ b/src/activity_handlers.cpp
@@ -4423,7 +4423,7 @@ void activity_handlers::robot_control_finish( player_activity *act, player *p )
                               z->name() );
         z->friendly = -1;
         if( z->has_flag( MF_RIDEABLE_MECH ) ) {
-            z->add_effect( effect_pet, 1_turns, num_bp );
+            z->add_effect( effect_pet, 1_turns );
         }
     } else if( success >= -2 ) {
         //A near success
diff --git a/src/armor_layers.cpp b/src/armor_layers.cpp
index 3e34692b7a04..c8958336ab25 100644
--- a/src/armor_layers.cpp
+++ b/src/armor_layers.cpp
@@ -78,7 +78,7 @@ item_penalties get_item_penalties( const location_vector<item>::const_iterator &
     std::vector<std::set<std::string>> lists_of_bad_items_within;
 
     for( const bodypart_id &bp : c.get_all_body_parts() ) {
-        if( _bp->token && _bp != body_part_appendix ) {
+        if( _bp->token && _bp.id().is_null() ) {
             continue;
         }
         if( !worn_item->covers( bp ) ) {
@@ -288,9 +288,9 @@ std::vector<std::string> clothing_properties(
     props.reserve( 5 );
 
     const std::string space = "  ";
-    const int coverage = bp == body_part_appendix ? worn_item.get_avg_coverage() :
+    const int coverage = bp.id().is_null() ? worn_item.get_avg_coverage() :
                          worn_item.get_coverage( bp );
-    const int encumbrance = bp == body_part_appendix ? worn_item.get_avg_encumber(
+    const int encumbrance = bp.id().is_null() ? worn_item.get_avg_encumber(
                                 c ) : worn_item.get_encumber( c, bp );
     props.push_back( string_format( "<color_c_green>[%s]</color>", _( "Properties" ) ) );
     props.push_back( name_and_value( space + _( "Coverage:" ),
@@ -436,7 +436,7 @@ void show_armor_layers_ui( Character &who )
     * + 3 - horizontal lines;
     * + 1 - caption line;
     * + 2 - innermost/outermost string lines;
-    * + num_bp - sub-categories (torso, head, eyes, etc.);
+    * + num_of_parts - sub-categories (torso, head, eyes, etc.);
     * + 1 - gap;
     * number of lines required for displaying all items is calculated dynamically,
     * because some items can have multiple entries (i.e. cover a few parts of body).
@@ -452,7 +452,7 @@ void show_armor_layers_ui( Character &who )
     for( const bodypart_id &it : all_parts ) {
         armor_cat.insert( it );
     }
-    armor_cat.insert( body_part_appendix );
+    armor_cat.insert( bodypart_str_id::NULL_ID().id() );
 
     int req_right_h = 3 + 1 + 2 + num_of_parts + 1;
     for( const bodypart_id &cover : armor_cat ) {
@@ -468,9 +468,9 @@ void show_armor_layers_ui( Character &who )
     * + 1 - caption line;
     * + 8 - general properties
     * + 13 - ASSUMPTION: max possible number of flags @ item
-    * + num_bp+1 - warmth & enc block
+    * + num_of_parts+1 - warmth & enc block
     */
-    const int req_mid_h = 3 + 1 + 8 + 13 + num_bp + 1;
+    const int req_mid_h = 3 + 1 + 8 + 13 + num_of_parts + 1;
 
     int win_h = 0;
     int win_w = 0;
@@ -542,7 +542,6 @@ void show_armor_layers_ui( Character &who )
     ctxt.register_action( "NEXT_TAB" );
     ctxt.register_action( "MOVE_ARMOR" );
     ctxt.register_action( "CHANGE_SIDE" );
-    ctxt.register_action( "TOGGLE_CLOTH" );
     ctxt.register_action( "ASSIGN_INVLETS" );
     ctxt.register_action( "SORT_ARMOR" );
     ctxt.register_action( "EQUIP_ARMOR" );
@@ -574,7 +573,7 @@ void show_armor_layers_ui( Character &who )
 
         // top bar
         wprintz( w_sort_cat, c_white, _( "Sort Armor" ) );
-        const auto name = bp != body_part_appendix ? body_part_name_as_heading( bp, 1 ) : _( "All" );
+        const auto name = bp.id() ? body_part_name_as_heading( bp, 1 ) : _( "All" );
         wprintz( w_sort_cat, c_yellow, "  << %s >>", name );
         right_print( w_sort_cat, 0, 0, c_white, string_format(
                          _( "[<color_yellow>%s</color>] Hide sprite.  "
@@ -678,7 +677,7 @@ void show_armor_layers_ui( Character &who )
         }
         int pos = 1, curr = 0;
         for( const bodypart_id cover : rl ) {
-            if( cover == body_part_appendix ) {
+            if( cover.id().is_null() ) {
                 continue;
             }
             if( curr >= rightListOffset && pos <= rightListLines ) {
@@ -743,7 +742,7 @@ void show_armor_layers_ui( Character &who )
         // Create ptr list of items to display
         tmp_worn.clear();
         const bodypart_id &bp = armor_cat[ tabindex ];
-        if( bp == body_part_appendix ) {
+        if( bp.id().is_null() ) {
             // All
             int i = 0;
             for( auto it = who.worn.begin(); it != who.worn.end(); ++it ) {
@@ -874,7 +873,7 @@ void show_armor_layers_ui( Character &who )
                 bool equipped = who.as_player()->wear_possessed( *loc );
                 if( equipped ) {
                     const bodypart_id &bp = armor_cat[tabindex];
-                    if( tabindex == num_bp || loc->covers( bp ) ) {
+                    if( tabindex == num_of_parts || loc->covers( bp ) ) {
                         // Set ourselves up to be pointing at the new item
                         // TODO: This doesn't work yet because we don't save our
                         // state through other activities, but that's a thing
@@ -886,7 +885,7 @@ void show_armor_layers_ui( Character &who )
                             if( i == loc ) {
                                 found = true;
                             }
-                            return !found && ( tabindex == num_bp || i->covers( bp ) );
+                            return !found && ( tabindex == num_of_parts || i->covers( bp ) );
                         } );
                     }
                 } else if( who.is_npc() ) {
diff --git a/src/bionics_ui.cpp b/src/bionics_ui.cpp
index a287dd6824f9..c4e8ef20e9ae 100644
--- a/src/bionics_ui.cpp
+++ b/src/bionics_ui.cpp
@@ -370,7 +370,8 @@ static void draw_bionics_tabs( const catacurses::window &win, const size_t activ
     wnoutrefresh( win );
 }
 
-static void draw_description( const catacurses::window &win, const bionic &bio )
+static void draw_description( const catacurses::window &win, const bionic &bio,
+                              const Character &who )
 {
     werase( win );
     const int width = getmaxx( win );
@@ -384,7 +385,8 @@ static void draw_description( const catacurses::window &win, const bionic &bio )
 
     // TODO: Unhide when enforcing limits
     if( get_option < bool >( "CBM_SLOTS_ENABLED" ) ) {
-        const bool each_bp_on_new_line = ypos + static_cast<int>( num_bp ) + 1 < getmaxy( win );
+        int body_part_count = who.get_all_body_parts().size();
+        const bool each_bp_on_new_line = ypos + body_part_count + 1 < getmaxy( win );
         fold_and_print( win, point( 0, ypos ), width, c_light_gray, list_occupied_bps( bio.id,
                         _( "This bionic occupies the following body parts:" ), each_bp_on_new_line ) );
     }
@@ -707,7 +709,7 @@ void show_bionics_ui( Character &who )
 
         draw_bionics_titlebar( w_title, &who, menu_mode );
         if( menu_mode == EXAMINING && !current_bionic_list->empty() ) {
-            draw_description( w_description, *( *current_bionic_list )[cursor] );
+            draw_description( w_description, *( *current_bionic_list )[cursor], who );
         }
     } );
 
diff --git a/src/character.cpp b/src/character.cpp
index 8be7ec3b6f10..b5707f15be09 100644
--- a/src/character.cpp
+++ b/src/character.cpp
@@ -1330,7 +1330,7 @@ void Character::forced_dismount()
         }
         const int dodge = get_dodge();
         const int damage = std::max( 0, rng( 1, 20 ) - rng( dodge, dodge * 2 ) );
-        bodypart_id hit( "num_bp" );
+        bodypart_id hit = bodypart_str_id::NULL_ID().id();
         switch( rng( 1, 10 ) ) {
             case  1:
                 if( one_in( 2 ) ) {
@@ -3175,25 +3175,23 @@ ret_val<bool> Character::can_wear( const item &it, bool with_equip_change ) cons
         }
         if( it.has_flag( flag_POWERARMOR_MOD ) ) {
             int max_layer = 2;
-            std::vector< std::pair< body_part, int > > mod_parts;
-            std::vector< std::pair< body_part, bool > > attachments;
-            body_part bp = num_bp;
-            bodypart_str_id bpid;
+            std::vector< std::pair< bodypart_str_id, int > > mod_parts;
+            std::vector< std::pair< bodypart_str_id, bool > > attachments;
             bool lhs = false;
             bool rhs = false;
-            for( std::size_t i = 0; i < static_cast< body_part >( num_bp ); ++i ) {
-                bp = static_cast< body_part >( i );
-                if( it.get_covered_body_parts().test( convert_bp( bp ) ) ) {
+            const auto &all_bps = get_all_body_parts();
+            for( const bodypart_id &bp : all_bps ) {
+                if( it.get_covered_body_parts().test( bp.id() ) ) {
                     mod_parts.emplace_back( bp, 0 );
                     attachments.emplace_back( bp, false );
                 }
             }
             for( auto &elem : worn ) {
                 // To check if there's an external/exoskeleton for the mod to attach to.
-                for( std::pair< body_part, bool > &attachment : attachments ) {
-                    if( elem->get_covered_body_parts().test( convert_bp( attachment.first ) ) &&
+                for( std::pair< bodypart_str_id, bool > &attachment : attachments ) {
+                    if( elem->get_covered_body_parts().test( attachment.first ) &&
                         ( elem->has_flag( flag_POWERARMOR_EXO ) || elem->has_flag( flag_POWERARMOR_EXTERNAL ) ) ) {
-                        if( elem->is_sided() && elem->get_side() == bpid->part_side ) {
+                        if( elem->is_sided() && elem->get_side() == attachment.first->part_side ) {
                             attachment.second = true;
                         } else {
                             attachment.second = true;
@@ -3201,11 +3199,10 @@ ret_val<bool> Character::can_wear( const item &it, bool with_equip_change ) cons
                     }
                 }
                 // To check how many mods are on a given part.
-                for( std::pair< body_part, int > &mod_part : mod_parts ) {
-                    bpid = convert_bp( mod_part.first );
-                    if( elem->get_covered_body_parts().test( bpid ) &&
+                for( std::pair< bodypart_str_id, int > &mod_part : mod_parts ) {
+                    if( elem->get_covered_body_parts().test( mod_part.first ) &&
                         elem->has_flag( flag_POWERARMOR_MOD ) ) {
-                        if( elem->is_sided() && elem->get_side() == bpid->part_side ) {
+                        if( elem->is_sided() && elem->get_side() == mod_part.first->part_side ) {
                             mod_part.second++;
                         } else {
                             mod_part.second++;
@@ -3213,21 +3210,20 @@ ret_val<bool> Character::can_wear( const item &it, bool with_equip_change ) cons
                     }
                 }
             }
-            for( std::pair< body_part, bool > &attachment : attachments ) {
+            for( std::pair< bodypart_str_id, bool > &attachment : attachments ) {
                 if( !attachment.second ) {
                     return ret_val<bool>::make_failure( _( "Nothing to attach the mod to!" ) );
                 }
             }
-            for( std::pair< body_part, int > &mod_part : mod_parts ) {
-                bpid = convert_bp( mod_part.first );
-                if( static_cast< body_part >( mod_part.first ) == bp_torso ) {
+            for( std::pair< bodypart_str_id, int > &mod_part : mod_parts ) {
+                if( mod_part.first == body_part_torso ) {
                     max_layer = 3;
                 }
                 if( mod_part.second >= max_layer ) {
-                    if( !it.is_sided() || bpid->part_side == side::BOTH ) {
+                    if( !it.is_sided() || mod_part.first->part_side == side::BOTH ) {
                         return ret_val<bool>::make_failure( _( "Can't wear any more mods on that body part!" ) );
                     } else {
-                        if( bpid->part_side == side::LEFT ) {
+                        if( mod_part.first->part_side == side::LEFT ) {
                             lhs = true;
                         } else {
                             rhs = true;
@@ -3483,27 +3479,23 @@ ret_val<bool> Character::can_swap( const item &it ) const
 {
     if( it.has_flag( flag_POWERARMOR_MOD ) ) {
         int max_layer = 2;
-        std::vector< std::pair< body_part, int > > mod_parts;
-        body_part bp = num_bp;
-        bodypart_str_id bpid;
-        for( std::size_t i = 0; i < static_cast< body_part >( num_bp ); ++i ) {
-            bp = static_cast< body_part >( i );
-            bpid = convert_bp( bp );
-            if( it.get_covered_body_parts().test( bpid ) && bpid->part_side != side::BOTH ) {
+        std::vector< std::pair< bodypart_str_id, int > > mod_parts;
+        const auto &all_bps = get_all_body_parts();
+        for( const bodypart_id &bp : all_bps ) {
+            if( it.get_covered_body_parts().test( bp.id() ) && bp->part_side != side::BOTH ) {
                 mod_parts.emplace_back( bp, 0 );
             }
         }
         for( auto &elem : worn ) {
-            for( std::pair< body_part, int > &mod_part : mod_parts ) {
-                bpid = convert_bp( mod_part.first );
+            for( std::pair< bodypart_str_id, int > &mod_part : mod_parts ) {
+                bodypart_str_id bpid = mod_part.first;
                 if( elem->get_covered_body_parts().test( bpid->opposite_part ) &&
                     elem->has_flag( flag_POWERARMOR_MOD ) ) {
                     mod_part.second++;
                 }
             }
         }
-        for( std::pair< body_part, int > &mod_part : mod_parts ) {
-            bpid = convert_bp( mod_part.first );
+        for( std::pair< bodypart_str_id, int > &mod_part : mod_parts ) {
             if( mod_part.second >= max_layer ) {
                 return ret_val<bool>::make_failure( _( "There is no space on the opposite side!" ) );
             }
@@ -4033,6 +4025,10 @@ char_encumbrance_data Character::calc_encumbrance( const item &new_item ) const
 {
 
     char_encumbrance_data enc;
+    // Make sure we have all body parts here, so that we can use ::at
+    for( const bodypart_id &bp : get_all_body_parts() ) {
+        enc.elems[bp.id()];
+    }
 
     item_encumb( enc, new_item );
     mut_cbm_encumb( enc );
@@ -4066,9 +4062,14 @@ char_encumbrance_data Character::get_encumbrance( const item &new_item ) const
     return calc_encumbrance( new_item );
 }
 
-int Character::extraEncumbrance( const layer_level level, const int bp ) const
+int Character::extra_encumbrance( layer_level level, const bodypart_str_id &bp ) const
 {
-    return encumbrance_cache->elems[bp].layer_penalty_details[static_cast<int>( level )].total;
+    auto iter = encumbrance_cache->elems.find( bp );
+    if( iter != encumbrance_cache->elems.end() ) {
+        return iter->second.layer_penalty_details[static_cast<int>( level )].total;
+    }
+
+    return 0;
 }
 
 bool Character::change_side( item &it, bool interactive )
@@ -4119,7 +4120,7 @@ bool Character::change_side( item *it, bool interactive )
 
 static void layer_item( char_encumbrance_data &vals,
                         const item &it,
-                        std::array<layer_level, num_bp> &highest_layer_so_far,
+                        std::map<bodypart_str_id, layer_level> &highest_layer_so_far,
                         const Character &c )
 {
     body_part_set covered_parts = it.get_covered_body_parts();
@@ -4146,17 +4147,17 @@ static void layer_item( char_encumbrance_data &vals,
             layering_encumbrance = 0;
         }
 
-        highest_layer_so_far[bp->token] =
-            std::max( highest_layer_so_far[bp->token], item_layer );
+        highest_layer_so_far[bp.id()] =
+            std::max( highest_layer_so_far[bp.id()], item_layer );
 
         // Apply layering penalty to this layer, as well as any layer worn
         // within it that would normally be worn outside of it.
         for( layer_level penalty_layer = item_layer;
-             penalty_layer <= highest_layer_so_far[bp->token]; ++penalty_layer ) {
-            vals.elems[bp->token].layer( penalty_layer, layering_encumbrance );
+             penalty_layer <= highest_layer_so_far[bp.id()]; ++penalty_layer ) {
+            vals.elems[bp.id()].layer( penalty_layer, layering_encumbrance );
         }
 
-        vals.elems[bp->token].armor_encumbrance += encumber_val;
+        vals.elems[bp.id()].armor_encumbrance += encumber_val;
     }
 }
 
@@ -4353,9 +4354,12 @@ void Character::item_encumb( char_encumbrance_data &vals, const item &new_item )
 
     // Track highest layer observed so far so we can penalize out-of-order
     // items
-    std::array<layer_level, num_bp> highest_layer_so_far;
-    std::fill( highest_layer_so_far.begin(), highest_layer_so_far.end(),
-               PERSONAL_LAYER );
+    std::map<bodypart_str_id, layer_level> highest_layer_so_far;
+    const auto &all_bps = get_all_body_parts();
+
+    for( const bodypart_id &bp : all_bps ) {
+        highest_layer_so_far[bp.id()] = PERSONAL_LAYER;
+    }
 
     for( auto w_it = worn.begin(); w_it != worn.end(); ++w_it ) {
         if( w_it == new_item_position ) {
@@ -4369,19 +4373,25 @@ void Character::item_encumb( char_encumbrance_data &vals, const item &new_item )
     }
 
     // make sure values are sane
-    for( const body_part bp : all_body_parts ) {
-        encumbrance_data &elem = vals.elems[bp];
+    for( const bodypart_id &bp : all_bps ) {
+        encumbrance_data &elem = vals.elems[bp.id()];
 
         elem.armor_encumbrance = std::max( 0, elem.armor_encumbrance );
 
         // Add armor and layering penalties for the final values
         elem.encumbrance += elem.armor_encumbrance + elem.layer_penalty;
     }
+    // @todo Debugmsg if there are bps not on our body list
 }
 
 int Character::encumb( const bodypart_str_id &bp ) const
 {
-    return encumbrance_cache->elems[bp->token].encumbrance;
+    const auto iter = encumbrance_cache->elems.find( bp );
+    if( iter != encumbrance_cache->elems.end() ) {
+        // @todo Debugmsg?
+        return iter->second.encumbrance;
+    }
+    return 0;
 }
 
 static void apply_mut_encumbrance( char_encumbrance_data &vals,
@@ -4389,12 +4399,12 @@ static void apply_mut_encumbrance( char_encumbrance_data &vals,
                                    const body_part_set &oversize )
 {
     for( const std::pair<const body_part, int> &enc : mut->encumbrance_always ) {
-        vals.elems[enc.first].encumbrance += enc.second;
+        vals.elems[convert_bp( enc.first )].encumbrance += enc.second;
     }
 
     for( const std::pair<const body_part, int> &enc : mut->encumbrance_covered ) {
         if( !oversize.test( convert_bp( enc.first ) ) ) {
-            vals.elems[enc.first].encumbrance += enc.second;
+            vals.elems[convert_bp( enc.first )].encumbrance += enc.second;
         }
     }
 }
@@ -4404,15 +4414,15 @@ void Character::mut_cbm_encumb( char_encumbrance_data &vals ) const
 
     for( const bionic_id &bid : get_bionics() ) {
         for( const std::pair<const bodypart_str_id, int> &element : bid->encumbrance ) {
-            vals.elems[element.first->token].encumbrance += element.second;
+            vals.elems[element.first].encumbrance += element.second;
         }
     }
 
     if( has_active_bionic( bio_shock_absorber ) ) {
         for( auto &val : vals.elems ) {
-            val.encumbrance += 3; // Slight encumbrance to all parts except eyes
+            val.second.encumbrance += 3; // Slight encumbrance to all parts except eyes
         }
-        vals.elems[bp_eyes].encumbrance -= 3;
+        vals.elems[body_part_eyes].encumbrance -= 3;
     }
 
     // Lower penalty for bps covered only by XL armor
@@ -5675,13 +5685,13 @@ void Character::update_bodytemp( const map &m, const weather_manager &weather )
     temp_equalizer( *this, body_part_leg_l, body_part_foot_l );
     temp_equalizer( *this, body_part_leg_r, body_part_foot_r );
 
+    const auto &all_bps = get_all_body_parts();
     for( const item * const &it : worn ) {
         // TODO: Port body part set id changes
         const body_part_set &covered = it->get_covered_body_parts();
-        for( size_t i = 0; i < num_bp; i++ ) {
-            body_part token = static_cast<body_part>( i );
-            if( covered.test( convert_bp( token ) ) ) {
-                clothing_map[convert_bp( token )].emplace_back( it );
+        for( const bodypart_id &bp : all_bps ) {
+            if( covered.test( bp.id() ) ) {
+                clothing_map[bp.id()].emplace_back( it );
             }
             if( it->has_flag( flag_HOOD ) ) {
                 bonus_clothing_map[body_part_head].emplace_back( it );
@@ -6154,10 +6164,10 @@ bodypart_str_id Character::body_window( const std::string &menu_header,
         const int current_hp = get_part_hp_cur( bp );
         // This will c_light_gray if the part does not have any effects cured by the item/effect
         // (e.g. it cures only bites, but the part does not have a bite effect)
-        const nc_color state_col = limb_color( bp, bleed > 0.0f, bite > 0.0f, infect > 0.0f );
+        const nc_color state_col = limb_color( bp.id(), bleed > 0.0f, bite > 0.0f, infect > 0.0f );
         const bool has_curable_effect = state_col != c_light_gray;
         // The same as in the main UI sidebar. Independent of the capability of the healing item/effect!
-        const nc_color all_state_col = limb_color( bp, true, true, true );
+        const nc_color all_state_col = limb_color( bp.id(), true, true, true );
         // Broken means no HP can be restored, it requires surgical attention.
         const bool limb_is_broken = is_limb_broken( bp );
 
@@ -6313,21 +6323,21 @@ bodypart_str_id Character::body_window( const std::string &menu_header,
     }
 }
 
-nc_color Character::limb_color( const bodypart_id &bp, bool bleed, bool bite, bool infect ) const
+nc_color Character::limb_color( const bodypart_str_id &bp, bool bleed, bool bite,
+                                bool infect ) const
 {
-    if( bp == bodypart_id( "num_bp" ) ) {
+    if( !bp ) {
         return c_light_gray;
     }
-    const bodypart_str_id &bp_str = bp.id();
     int color_bit = 0;
     nc_color i_color = c_light_gray;
-    if( bleed && has_effect( effect_bleed, bp_str ) ) {
+    if( bleed && has_effect( effect_bleed, bp ) ) {
         color_bit += 1;
     }
-    if( bite && has_effect( effect_bite, bp_str ) ) {
+    if( bite && has_effect( effect_bite, bp ) ) {
         color_bit += 10;
     }
-    if( infect && has_effect( effect_infected, bp_str ) ) {
+    if( infect && has_effect( effect_infected, bp ) ) {
         color_bit += 100;
     }
     switch( color_bit ) {
@@ -6838,13 +6848,9 @@ std::string Character::extended_description() const
     // This is a stripped-down version of the body_window function
     // This should be extracted into a separate function later on
     for( const bodypart_id &bp : bps ) {
-        // Hide appendix from the player
-        if( bp->id.str() == "num_bp" ) {
-            continue;
-        }
         const std::string &bp_heading = body_part_name_as_heading( bp->token, 1 );
 
-        const nc_color state_col = limb_color( bp, true, true, true );
+        const nc_color state_col = limb_color( bp.id(), true, true, true );
         nc_color name_color = state_col;
         std::pair<std::string, nc_color> hp_bar = get_hp_bar( get_part_hp_cur( bp ), get_part_hp_max( bp ),
                 false );
@@ -8750,7 +8756,7 @@ void Character::apply_damage( Creature *source, item *source_weapon, item *sourc
         return;
     }
 
-    if( hurt == bodypart_id( "num_bp" ) ) {
+    if( hurt.id().is_null() ) {
         debugmsg( "Wacky body part hurt!" );
         hurt = bodypart_id( "torso" );
     }
@@ -8822,8 +8828,7 @@ dealt_damage_instance Character::deal_damage( Creature *source, bodypart_id bp,
         return dealt_damage_instance();
     }
 
-    const body_part bp_token = bp->token;
-    if( bp_token == num_bp ) {
+    if( bp.id().is_null() ) {
         debugmsg( "Wacky bodypart hit!" );
         return dealt_damage_instance();
     }
diff --git a/src/character.h b/src/character.h
index 84514a24ee84..357dadac41d6 100644
--- a/src/character.h
+++ b/src/character.h
@@ -499,7 +499,7 @@ class Character : public Creature, public location_visitable<Character>
         /** Get encumbrance for all body parts as if `new_item` was also worn. */
         char_encumbrance_data get_encumbrance( const item &new_item ) const;
         /** Get encumbrance penalty per layer & body part */
-        int extraEncumbrance( layer_level level, int bp ) const;
+        int extra_encumbrance( layer_level level, const bodypart_str_id &bp ) const;
 
         /** Returns true if the character is wearing power armor */
         bool is_wearing_power_armor( bool *hasHelmet = nullptr ) const;
@@ -798,7 +798,7 @@ class Character : public Creature, public location_visitable<Character>
                                      float bleed, float bite, float infect, float bandage_power, float disinfectant_power ) const;
 
         // Returns color which this limb would have in healing menus
-        nc_color limb_color( const bodypart_id &bp, bool bleed, bool bite, bool infect ) const;
+        nc_color limb_color( const bodypart_str_id &bp, bool bleed, bool bite, bool infect ) const;
 
         static const std::vector<material_id> fleshy;
         bool made_of( const material_id &m ) const override;
diff --git a/src/character_display.cpp b/src/character_display.cpp
index 10fb99b3e5aa..9b31390152b0 100644
--- a/src/character_display.cpp
+++ b/src/character_display.cpp
@@ -64,11 +64,6 @@ static int get_temp_conv( const Character &c, const bodypart_str_id &bp )
     return iter->second.get_temp_conv();
 }
 
-static int get_temp_conv( const Character &c, body_part bp )
-{
-    return get_temp_conv( c, convert_bp( bp ) );
-}
-
 nc_color warmth::bodytemp_color( const Character &c, const bodypart_str_id &bp )
 {
     if( bp == body_part_eyes ) {
@@ -100,39 +95,35 @@ static int temperature_print_rescaling( int temp )
     return ( temp / 100.0 ) * 2 - 100;
 }
 
-static body_part other_part( body_part bp )
-{
-    return static_cast<body_part>( bp_aiOther[bp] );
-}
-
-static bool should_combine_bps( const Character &ch, body_part l, body_part r,
+static bool should_combine_bps( const Character &ch,
+                                const bodypart_str_id &l, const bodypart_str_id &r,
                                 const item *selected_clothing )
 {
     const char_encumbrance_data enc_data = ch.get_encumbrance();
     return l != r && // are different parts
-           l == other_part( r ) && r == other_part( l ) && // are complementary parts
+           l == r->opposite_part && r == l->opposite_part && // are complementary parts
            // same encumberance & temperature
-           enc_data.elems[l] == enc_data.elems[r] &&
+           // @todo Is ::at safe here?
+           enc_data.elems.at( l ) == enc_data.elems.at( r ) &&
            temperature_print_rescaling( get_temp_conv( ch,
                                         l ) ) == temperature_print_rescaling( get_temp_conv( ch, r ) ) &&
            // selected_clothing covers both or neither parts
            ( !selected_clothing ||
-             ( selected_clothing->covers( convert_bp( l ).id() ) == selected_clothing->covers( convert_bp(
-                         r ).id() ) ) );
+             ( selected_clothing->covers( l.id() ) == selected_clothing->covers( r.id() ) ) );
 }
 
-static std::vector<std::pair<body_part, bool>> list_and_combine_bps( const Character &ch,
+static std::vector<std::pair<bodypart_str_id, bool>> list_and_combine_bps( const Character &ch,
         const item *selected_clothing )
 {
     // bool represents whether the part has been combined with its other half
-    std::vector<std::pair<body_part, bool>> bps;
-    for( auto bp : all_body_parts ) {
+    std::vector<std::pair<bodypart_str_id, bool>> bps;
+    for( auto bp : ch.get_all_body_parts() ) {
         // assuming that a body part has at most one other half
-        if( other_part( other_part( bp ) ) != bp ) {
-            debugmsg( "Bodypart %d has more than one other half!", bp );
+        if( bp->opposite_part->opposite_part != bp.id() ) {
+            debugmsg( "Bodypart %s has more than one other half!", bp.id().c_str() );
         }
-        if( should_combine_bps( ch, bp, other_part( bp ), selected_clothing ) ) {
-            if( bp < other_part( bp ) ) {
+        if( should_combine_bps( ch, bp.id(), bp->opposite_part, selected_clothing ) ) {
+            if( bp.to_i() < bp->opposite_part.id().to_i() ) {
                 // only add the earlier one
                 bps.emplace_back( bp, true );
             }
@@ -168,7 +159,8 @@ void character_display::print_encumbrance( ui_adaptor &ui, const catacurses::win
         const int line, const item *selected_clothing )
 {
     // bool represents whether the part has been combined with its other half
-    const std::vector<std::pair<body_part, bool>> bps = list_and_combine_bps( ch, selected_clothing );
+    const std::vector<std::pair<bodypart_str_id, bool>> bps = list_and_combine_bps( ch,
+            selected_clothing );
 
     // width/height excluding title & scrollbar
     const int height = getmaxy( win ) - 1;
@@ -191,11 +183,10 @@ void character_display::print_encumbrance( ui_adaptor &ui, const catacurses::win
         if( static_cast<size_t>( thisline ) >= bps.size() ) {
             break;
         }
-        const body_part bp = bps[thisline].first;
+        const bodypart_str_id &bp = bps[thisline].first;
         const bool combine = bps[thisline].second;
-        const encumbrance_data &e = enc_data.elems[bp];
-        const bool highlighted = selected_clothing ? selected_clothing->covers( convert_bp(
-                                     bp ).id() ) : false;
+        const encumbrance_data &e = enc_data.elems.at( bp );
+        const bool highlighted = selected_clothing ? selected_clothing->covers( bp.id() ) : false;
         std::string out = body_part_name_as_heading( bp, combine ? 2 : 1 );
         if( utf8_width( out ) > 7 ) {
             out = utf8_truncate( out, 7 );
@@ -221,7 +212,7 @@ void character_display::print_encumbrance( ui_adaptor &ui, const catacurses::win
         mvwprintz( win, point( 12, y_pos ), encumb_color( e.encumbrance ), "%-3d", e.layer_penalty );
         // print warmth, tethered to right hand side of the window
 
-        mvwprintz( win, point( width - 6, y_pos ), warmth::bodytemp_color( ch, convert_bp( bp ) ), "(% 3d)",
+        mvwprintz( win, point( width - 6, y_pos ), warmth::bodytemp_color( ch, bp ), "(% 3d)",
                    temperature_print_rescaling( get_temp_conv( ch, bp ) ) );
     }
 
@@ -276,13 +267,14 @@ static int get_encumbrance( const Character &p, body_part bp, bool combine )
     return p.encumb( convert_bp( bp ) ) * ( ( combine && combines_with_other ) ? 2 : 1 );
 }
 
-static std::string get_encumbrance_description( const Character &p, body_part bp, bool combine )
+static std::string get_encumbrance_description( const Character &p, const bodypart_str_id &bp,
+        bool combine )
 {
     std::string s;
 
-    const int eff_encumbrance = get_encumbrance( p, bp, combine );
+    const int eff_encumbrance = get_encumbrance( p, bp->token, combine );
 
-    switch( bp ) {
+    switch( bp->token ) {
         case bp_torso: {
             const int melee_roll_pen = std::max( -eff_encumbrance, -80 );
             s += string_format( _( "Melee attack rolls: <color_white>%+d%%</color>\n" ), melee_roll_pen );
@@ -554,10 +546,10 @@ static void draw_encumbrance_tab( ui_adaptor &ui, const catacurses::window &w_en
 static void draw_encumbrance_info( const catacurses::window &w_info, const Character &you,
                                    const unsigned line )
 {
-    const std::vector<std::pair<body_part, bool>> bps = list_and_combine_bps( you, nullptr );
+    const std::vector<std::pair<bodypart_str_id, bool>> bps = list_and_combine_bps( you, nullptr );
 
     werase( w_info );
-    body_part bp = num_bp;
+    bodypart_str_id bp;
     bool combined_here = false;
     if( line < bps.size() ) {
         bp = bps[line].first;
@@ -1118,7 +1110,7 @@ static bool handle_player_display_action( Character &you, unsigned int &line,
             line_end = 6;
             break;
         case player_display_tab::encumbrance: {
-            const std::vector<std::pair<body_part, bool>> bps = list_and_combine_bps( you, nullptr );
+            const std::vector<std::pair<bodypart_str_id, bool>> bps = list_and_combine_bps( you, nullptr );
             line_end = bps.size();
             break;
         }
diff --git a/src/character_encumbrance.h b/src/character_encumbrance.h
index aa610d635a10..d4416445cccb 100644
--- a/src/character_encumbrance.h
+++ b/src/character_encumbrance.h
@@ -49,7 +49,7 @@ struct encumbrance_data {
 };
 
 struct char_encumbrance_data {
-    std::array<encumbrance_data, num_bp> elems;
+    std::map<bodypart_str_id, encumbrance_data> elems;
 };
 
 #endif // CATA_SRC_CHARACTER_ENCUMBRANCE_H
diff --git a/src/character_functions.cpp b/src/character_functions.cpp
index db417baaeead..770919d05bc4 100644
--- a/src/character_functions.cpp
+++ b/src/character_functions.cpp
@@ -474,12 +474,12 @@ std::string fmt_wielded_weapon( const Character &who )
     }
 }
 
-void add_pain_msg( const Character &who, int val, body_part bp )
+void add_pain_msg( const Character &who, int val, const bodypart_str_id &bp )
 {
     if( who.has_trait( trait_NOPAIN ) ) {
         return;
     }
-    if( bp == num_bp ) {
+    if( !bp ) {
         if( val > 20 ) {
             who.add_msg_if_player( _( "Your body is wracked with excruciating pain!" ) );
         } else if( val > 10 ) {
@@ -494,19 +494,19 @@ void add_pain_msg( const Character &who, int val, body_part bp )
     } else {
         if( val > 20 ) {
             who.add_msg_if_player( _( "Your %s is wracked with excruciating pain!" ),
-                                   body_part_name_accusative( bp ) );
+                                   body_part_name_accusative( bp.id() ) );
         } else if( val > 10 ) {
             who.add_msg_if_player( _( "Your %s is wracked with terrible pain!" ),
-                                   body_part_name_accusative( bp ) );
+                                   body_part_name_accusative( bp.id() ) );
         } else if( val > 5 ) {
             who.add_msg_if_player( _( "Your %s is wracked with pain!" ),
-                                   body_part_name_accusative( bp ) );
+                                   body_part_name_accusative( bp.id() ) );
         } else if( val > 1 ) {
             who.add_msg_if_player( _( "Your %s pains you!" ),
-                                   body_part_name_accusative( bp ) );
+                                   body_part_name_accusative( bp.id() ) );
         } else {
             who.add_msg_if_player( _( "Your %s aches." ),
-                                   body_part_name_accusative( bp ) );
+                                   body_part_name_accusative( bp.id() ) );
         }
     }
 }
diff --git a/src/character_functions.h b/src/character_functions.h
index 3a073c2edbbc..cb9422ee8b4b 100644
--- a/src/character_functions.h
+++ b/src/character_functions.h
@@ -118,9 +118,9 @@ std::string fmt_wielded_weapon( const Character &who );
  * Add message describing how character feels pain.
  * @param who Character that feels the pain
  * @param val Amount of pain
- * @param bp Target body part, use num_bp if no specific body part.
+ * @param bp Target body part, use bodypart_str_id::NULL_ID() if no specific body part. @todo Consider std::optional?
  */
-void add_pain_msg( const Character &who, int val, body_part bp );
+void add_pain_msg( const Character &who, int val, const bodypart_str_id &bp );
 
 /** Reset Character's weapon and body state (limb hp, stamina, active martial art) */
 void normalize( Character &who );
diff --git a/src/character_turn.cpp b/src/character_turn.cpp
index 086a3ce4a18d..90c9589b28ca 100644
--- a/src/character_turn.cpp
+++ b/src/character_turn.cpp
@@ -339,7 +339,7 @@ void Character::process_one_effect( effect &it, bool is_new )
 {
     bool reduced = resists_effect( it );
     double mod = 1;
-    body_part bp = it.get_bp()->token;
+    bodypart_str_id bp = it.get_bp();
     int val = 0;
 
     // Still hardcoded stuff, do this first since some modify their other traits
@@ -489,7 +489,7 @@ void Character::process_one_effect( effect &it, bool is_new )
             }
         }
         if( is_new || it.activated( calendar::turn, "HURT", val, reduced, mod ) ) {
-            if( bp == num_bp ) {
+            if( !bp ) {
                 if( val > 5 ) {
                     add_msg_if_player( _( "Your %s HURTS!" ), body_part_name_accusative( bp_torso ) );
                 } else {
@@ -502,7 +502,7 @@ void Character::process_one_effect( effect &it, bool is_new )
                 } else {
                     add_msg_if_player( _( "Your %s hurts!" ), body_part_name_accusative( bp ) );
                 }
-                apply_damage( nullptr, convert_bp( bp ).id(), val, true );
+                apply_damage( nullptr, bp.id(), val, true );
             }
         }
     }
diff --git a/src/creature.cpp b/src/creature.cpp
index 2623c073312a..3a8a73247231 100644
--- a/src/creature.cpp
+++ b/src/creature.cpp
@@ -589,7 +589,7 @@ void Creature::deal_melee_hit( Creature *source, item *source_weapon, int hit_sp
                                const damage_instance &dam, dealt_damage_instance &dealt_dam )
 {
     if( source == nullptr || source->is_hallucination() ) {
-        dealt_dam.bp_hit = anatomy_id( "human_anatomy" )->random_body_part()->token;
+        dealt_dam.bp_hit = anatomy_id( "human_anatomy" )->random_body_part().id();
         return;
     }
     // If carrying a rider, there is a chance the hits may hit rider instead.
@@ -607,12 +607,11 @@ void Creature::deal_melee_hit( Creature *source, item *source_weapon, int hit_sp
     }
     damage_instance d = dam; // copy, since we will mutate in block_hit
     bodypart_id bp_hit = select_body_part( source, hit_spread ).id();
-    const body_part bp_token = bp_hit->token;
     block_hit( source, bp_hit, d );
 
     on_hit( source, bp_hit ); // trigger on-gethit events
     dealt_dam = deal_damage( source, bp_hit, d, source_weapon );
-    dealt_dam.bp_hit = bp_token;
+    dealt_dam.bp_hit = bp_hit.id();
 }
 void Creature::deal_melee_hit( Creature *source, int hit_spread, bool critical_hit,
                                const damage_instance &dam, dealt_damage_instance &dealt_dam )
@@ -647,11 +646,11 @@ void print_dmg_msg( Creature &target, Creature *source, const dealt_damage_insta
     if( dealt_dam.total_damage() == 0 ) {
         //~ 1$ - monster name, 2$ - character's bodypart or monster's skin/armor
         add_msg( _( "The shot reflects off %1$s %2$s!" ), target.disp_name( true ),
-                 ( target.is_monster() || dealt_dam.bp_hit == num_bp ) ?
+                 ( target.is_monster() || !dealt_dam.bp_hit ) ?
                  target.skin_name() :
-                 body_part_name_accusative( dealt_dam.bp_hit ) );
+                 dealt_dam.bp_hit->accusative.translated() );
     } else if( target.is_player() ) {
-        if( dealt_dam.bp_hit != bodypart_str_id::NULL_ID()->token ) {
+        if( dealt_dam.bp_hit ) {
             //monster hits player ranged
             //~ Hit message. 1$s is bodypart name in accusative. 2$d is damage value.
             target.add_msg_if_player( m_bad, _( "You were hit in the %1$s for %2$d damage." ),
@@ -861,7 +860,7 @@ void Creature::deal_projectile_attack( Creature *source, item *source_weapon,
     block_ranged_hit( source, bp_hit, impact );
     // If the projectile survives, both it and the launcher get credit for the kill.
     dealt_dam = deal_damage( source, bp_hit, impact, source_weapon, attack.proj.get_drop() );
-    dealt_dam.bp_hit = bp_hit->token;
+    dealt_dam.bp_hit = bp_hit.id();
 
     // Apply ammo effects to target.
     if( proj.has_effect( ammo_effect_TANGLE ) ) {
@@ -872,7 +871,7 @@ void Creature::deal_projectile_attack( Creature *source, item *source_weapon,
         if( z ) {
             detached_ptr<item> drop_item = proj.unset_drop();
             if( drop_item ) {
-                z->add_effect( effect_tied, 1_turns, num_bp );
+                z->add_effect( effect_tied, 1_turns );
                 z->set_tied_item( std::move( drop_item ) );
             } else {
                 add_msg( m_debug, "projectile with TANGLE effect, but no drop item specified" );
@@ -1264,7 +1263,7 @@ bool Creature::remove_effect( const efftype_id &eff_id, const bodypart_str_id &b
         g->events().send<event_type::character_loses_effect>( ch->getID(), eff_id );
     }
 
-    // num_bp means remove all of a given effect id
+    // null bp means remove all of a given effect id
     if( !bp ) {
         for( auto &it : ( *effects )[eff_id] ) {
             auto &e = it.second;
@@ -1291,7 +1290,7 @@ bool Creature::has_effect( const efftype_id &eff_id ) const
 }
 bool Creature::has_effect( const efftype_id &eff_id, const bodypart_str_id &bp ) const
 {
-    // num_bp means anything targeted or not
+    // null bp means anything, non-null means only that bp
     if( !bp ) {
         auto got = effects->find( eff_id );
         return got != effects->end() && !got->second.begin()->second.is_removed();
@@ -1840,7 +1839,7 @@ std::vector<bodypart_id> Creature::get_all_body_parts( bool only_main ) const
 
 int Creature::get_hp( const bodypart_id &bp ) const
 {
-    if( bp != bodypart_id( "num_bp" ) ) {
+    if( bp ) {
         return get_part_hp_cur( bp );
     }
     int hp_total = 0;
@@ -1852,12 +1851,12 @@ int Creature::get_hp( const bodypart_id &bp ) const
 
 int Creature::get_hp() const
 {
-    return get_hp( bodypart_id( "num_bp" ) );
+    return get_hp( bodypart_str_id::NULL_ID().id() );
 }
 
 int Creature::get_hp_max( const bodypart_id &bp ) const
 {
-    if( bp != bodypart_id( "num_bp" ) ) {
+    if( bp ) {
         return get_part_hp_max( bp );
     }
     int hp_total = 0;
@@ -1869,7 +1868,7 @@ int Creature::get_hp_max( const bodypart_id &bp ) const
 
 int Creature::get_hp_max() const
 {
-    return get_hp_max( bodypart_id( "num_bp" ) );
+    return get_hp_max( bodypart_str_id::NULL_ID().id() );
 }
 
 int Creature::get_speed_base() const
diff --git a/src/damage.h b/src/damage.h
index aafa70fc3218..5227c702b2bb 100644
--- a/src/damage.h
+++ b/src/damage.h
@@ -108,7 +108,7 @@ struct damage_instance {
 
 struct dealt_damage_instance {
     std::array<int, NUM_DT> dealt_dams;
-    body_part bp_hit;
+    bodypart_str_id bp_hit;
 
     dealt_damage_instance();
     void set_damage( damage_type dt, int amount );
diff --git a/src/effect.cpp b/src/effect.cpp
index 2ed80b6e8dfe..b9bd65cade6c 100644
--- a/src/effect.cpp
+++ b/src/effect.cpp
@@ -600,7 +600,7 @@ std::string effect::disp_name() const
             }
         }
     }
-    if( bp != num_bp ) {
+    if( bp ) {
         ret += string_format( " (%s)", body_part_name( bp ) );
     }
 
@@ -850,7 +850,7 @@ time_point effect::get_start_time() const
 
 const bodypart_str_id &effect::get_bp() const
 {
-    return convert_bp( bp );
+    return bp;
 }
 
 bool effect::is_permanent() const
@@ -1456,7 +1456,7 @@ void effect::serialize( JsonOut &json ) const
     json.start_object();
     json.member( "eff_type", eff_type != nullptr ? eff_type->id.str() : "" );
     json.member( "duration", duration );
-    json.member( "bp", static_cast<int>( bp ) );
+    json.member( "bp", bp );
     json.member( "intensity", intensity );
     json.member( "start_turn", start_time );
     // Legacy
@@ -1471,7 +1471,13 @@ void effect::deserialize( JsonIn &jsin )
     const efftype_id id( jo.get_string( "eff_type" ) );
     eff_type = &id.obj();
     jo.read( "duration", duration );
-    bp = static_cast<body_part>( jo.get_int( "bp" ) );
+    // @todo Remove after stable
+    if( jo.has_int( "bp" ) ) {
+        bp = convert_bp( static_cast<body_part>( jo.get_int( "bp" ) ) );
+    } else {
+        bp = bodypart_str_id( jo.get_string( "bp" ) );
+
+    }
     intensity = jo.get_int( "intensity" );
     start_time = calendar::turn_zero;
     jo.read( "start_turn", start_time );
@@ -1584,7 +1590,7 @@ std::vector<effect> effect::create_child_effects( bool decay ) const
         const effect_type *new_effect_type = &*new_effect.type;
         time_duration dur = new_effect.inherit_duration ? this->duration : new_effect.duration;
         int intensity = new_effect.inherit_intensity ? this->intensity : new_effect.intensity;
-        bodypart_str_id bp = new_effect.inherit_body_part ? convert_bp( this->bp ) : new_effect.bp;
+        bodypart_str_id bp = new_effect.inherit_body_part ? this->bp : new_effect.bp;
         effect e = effect( new_effect_type, dur, bp, intensity, calendar::turn );
         ret.emplace_back( e );
     }
diff --git a/src/effect.h b/src/effect.h
index 127445ca72d1..d639b5219b98 100644
--- a/src/effect.h
+++ b/src/effect.h
@@ -218,13 +218,13 @@ class effect_type
 class effect
 {
     public:
-        effect() : eff_type( nullptr ), duration( 0_turns ), bp( num_bp ),
+        effect() : eff_type( nullptr ), duration( 0_turns ), bp(),
             intensity( 1 ), start_time( calendar::turn_zero ),
             removed( true ) {
         }
         effect( const effect_type *peff_type, const time_duration &dur,
                 const bodypart_str_id &part, int nintensity, const time_point &nstart_time ) :
-            eff_type( peff_type ), duration( dur ), bp( part->token ),
+            eff_type( peff_type ), duration( dur ), bp( part ),
             intensity( nintensity ), start_time( nstart_time ),
             removed( false ) {
         }
@@ -378,7 +378,7 @@ class effect
     protected:
         const effect_type *eff_type;
         time_duration duration;
-        body_part bp;
+        bodypart_str_id bp;
         int intensity;
         time_point start_time;
         bool removed;
diff --git a/src/game.cpp b/src/game.cpp
index 460c6f458566..d03f8170f588 100644
--- a/src/game.cpp
+++ b/src/game.cpp
@@ -740,7 +740,7 @@ bool game::start_game()
     for( const mtype_id &elem : u.starting_pets ) {
         if( monster *const mon = place_critter_around( elem, u.pos(), 5 ) ) {
             mon->friendly = -1;
-            mon->add_effect( effect_pet, 1_turns, num_bp );
+            mon->add_effect( effect_pet, 1_turns );
         } else {
             add_msg( m_debug, "cannot place starting pet, no space!" );
         }
@@ -4893,14 +4893,14 @@ bool game::revive_corpse( const tripoint &p, item &it )
     }
 
     critter.no_extra_death_drops = true;
-    critter.add_effect( effect_downed, 5_turns, num_bp );
+    critter.add_effect( effect_downed, 5_turns );
     for( detached_ptr<item> &component : it.remove_components() ) {
         critter.add_corpse_component( std::move( component ) );
     }
 
     if( it.get_var( "zlave" ) == "zlave" ) {
-        critter.add_effect( effect_pacified, 1_turns, num_bp );
-        critter.add_effect( effect_pet, 1_turns, num_bp );
+        critter.add_effect( effect_pacified, 1_turns );
+        critter.add_effect( effect_pet, 1_turns );
     }
 
     if( it.get_var( "no_ammo" ) == "no_ammo" ) {
diff --git a/src/item.cpp b/src/item.cpp
index 2a61c50f788b..e91f88c5351c 100644
--- a/src/item.cpp
+++ b/src/item.cpp
@@ -4502,23 +4502,21 @@ void item::on_wear( Character &p )
             }
         } else if( has_flag( flag_POWERARMOR_MOD ) ) {
             // for power armor mods, wear on side with least mods
-            std::vector< std::pair< body_part, int > > mod_parts;
-            body_part bp = num_bp;
-            bodypart_str_id bpid;
+            std::vector< std::pair< bodypart_str_id, int > > mod_parts;
             int lhs = 0;
             int rhs = 0;
-            for( std::size_t i = 0; i < static_cast< body_part >( num_bp ) ; ++i ) {
-                bp = static_cast< body_part >( i );
-                if( get_covered_body_parts().test( convert_bp( bp ) ) ) {
+            const auto &all_bps = p.get_all_body_parts();
+            for( const bodypart_id &bp : all_bps ) {
+                if( get_covered_body_parts().test( bp.id() ) ) {
                     mod_parts.emplace_back( bp, 0 );
                 }
             }
             for( auto &elem : p.worn ) {
-                for( std::pair< body_part, int > &mod_part : mod_parts ) {
-                    bpid = convert_bp( mod_part.first );
-                    if( elem->get_covered_body_parts().test( bpid ) &&
+                for( std::pair< bodypart_str_id, int > &mod_part : mod_parts ) {
+                    const bodypart_str_id &bp = mod_part.first;
+                    if( elem->get_covered_body_parts().test( bp ) &&
                         elem->has_flag( flag_POWERARMOR_MOD ) ) {
-                        if( elem->is_sided() && elem->get_side() == bpid->part_side ) {
+                        if( elem->is_sided() && elem->get_side() == bp->part_side ) {
                             mod_part.second++;
                             continue;
                         }
@@ -4526,31 +4524,30 @@ void item::on_wear( Character &p )
                     }
                 }
             }
-            for( std::pair< body_part, int > &mod_part : mod_parts ) {
-                bpid = convert_bp( mod_part.first );
-                if( bpid->part_side == side::LEFT && mod_part.second > lhs ) {
-                    add_msg( _( "left" ) );
+            for( std::pair< bodypart_str_id, int > &mod_part : mod_parts ) {
+                const bodypart_str_id &bp = mod_part.first;
+                if( bp->part_side == side::LEFT && mod_part.second > lhs ) {
                     lhs = mod_part.second;
-                } else if( bpid->part_side == side::RIGHT && mod_part.second > rhs ) {
-                    add_msg( _( "right" ) );
+                } else if( bp->part_side == side::RIGHT && mod_part.second > rhs ) {
                     rhs = mod_part.second;
                 }
             }
             set_side( ( lhs > rhs ) ? side::RIGHT : side::LEFT );
         } else {
             // for sided items wear the item on the side which results in least encumbrance
+            const auto &all_bps = p.get_all_body_parts();
             int lhs = 0;
             int rhs = 0;
             set_side( side::LEFT );
             const char_encumbrance_data left_enc = p.get_encumbrance( *this );
-            for( const body_part bp : all_body_parts ) {
-                lhs += left_enc.elems[bp].encumbrance;
+            for( const bodypart_id &bp : all_bps ) {
+                lhs += left_enc.elems.at( bp.id() ).encumbrance;
             }
 
             set_side( side::RIGHT );
             const char_encumbrance_data right_enc = p.get_encumbrance( *this );
-            for( const body_part bp : all_body_parts ) {
-                rhs += right_enc.elems[bp].encumbrance;
+            for( const bodypart_id &bp : all_bps ) {
+                rhs += right_enc.elems.at( bp.id() ).encumbrance;
             }
 
             set_side( lhs <= rhs ? side::LEFT : side::RIGHT );
diff --git a/src/iteminfo_armor.cpp b/src/iteminfo_armor.cpp
index 42708c26df4b..2ad6b4d2415e 100644
--- a/src/iteminfo_armor.cpp
+++ b/src/iteminfo_armor.cpp
@@ -339,7 +339,7 @@ void item::armor_info( std::vector<iteminfo> &info, const iteminfo_query *parts,
                     continue;
                 }
                 for( const bodypart_str_id &covering_id : piece.covers ) {
-                    if( covering_id != bodypart_str_id( "num_bp" ) ) {
+                    if( covering_id ) {
                         const int encumbrance_when_full =
                             get_encumber_when_containing( you, get_total_capacity(), covering_id.id() );
                         to_display_data[covering_id] = { covering_id.obj().name_as_heading, {
diff --git a/src/iuse.cpp b/src/iuse.cpp
index 6f87d4fbadd9..c52298cf0412 100644
--- a/src/iuse.cpp
+++ b/src/iuse.cpp
@@ -4306,7 +4306,7 @@ int iuse::dog_whistle( player *p, item *it, bool, const tripoint & )
                 if( u_see ) {
                     p->add_msg_if_player( _( "Your %s goes docile." ), critter.name() );
                 }
-                critter.add_effect( effect_docile, 1_turns, num_bp );
+                critter.add_effect( effect_docile, 1_turns );
             }
         }
     }
@@ -4979,7 +4979,7 @@ int iuse::artifact( player *p, item *it, bool, const tripoint & )
                     for( int j = 0; j < num; j++ ) {
                         if( monster *const b = g->place_critter_around( bug, p->pos(), 1 ) ) {
                             b->friendly = -1;
-                            b->add_effect( effect_pet, 1_turns, num_bp );
+                            b->add_effect( effect_pet, 1_turns );
                         }
                     }
                 }
@@ -5757,7 +5757,7 @@ int iuse::robotcontrol( player *p, item *it, bool, const tripoint & )
                 if( critter.friendly != 0 && critter.type->in_species( ROBOT ) ) {
                     p->add_msg_if_player( _( "A following %s goes into passive mode." ),
                                           critter.name() );
-                    critter.add_effect( effect_docile, 1_turns, num_bp );
+                    critter.add_effect( effect_docile, 1_turns );
                     f = 1;
                 }
             }
@@ -8004,7 +8004,7 @@ static bool multicooker_hallu( player &p )
                 add_msg( m_warning, _( "The multi-cooker runs away!" ) );
                 if( monster *const m = g->place_critter_around( mon_hallu_multicooker, p.pos(), 1 ) ) {
                     m->hallucination = true;
-                    m->add_effect( effect_run, 100_turns, num_bp );
+                    m->add_effect( effect_run, 100_turns );
                 }
             } else {
                 p.add_msg_if_player( m_info, _( "You're surrounded by aggressive multi-cookers!" ) );
diff --git a/src/iuse_actor.cpp b/src/iuse_actor.cpp
index 3cebfd5cd9d2..abed5e974ee4 100644
--- a/src/iuse_actor.cpp
+++ b/src/iuse_actor.cpp
@@ -1125,7 +1125,7 @@ int place_monster_iuse::use( player &p, item &it, bool, const tripoint &pos ) co
         }
         newmon.friendly = -1;
         if( is_pet ) {
-            newmon.add_effect( effect_pet, 1_turns, num_bp );
+            newmon.add_effect( effect_pet, 1_turns );
         }
     }
     // Transfer label from the item to monster nickname
diff --git a/src/magic_spell_effect.cpp b/src/magic_spell_effect.cpp
index 260d437766d2..ef23c27e1536 100644
--- a/src/magic_spell_effect.cpp
+++ b/src/magic_spell_effect.cpp
@@ -151,7 +151,7 @@ void spell_effect::pain_split( const spell &sp, Creature &caster, const tripoint
     int total_hp = 0; // total hp among limbs
 
     for( const std::pair<const bodypart_str_id, bodypart> &elem : p->get_body() ) {
-        if( elem.first == bodypart_str_id( "num_bp" ) ) {
+        if( !elem.first ) {
             continue;
         }
         num_limbs++;
diff --git a/src/map_field.cpp b/src/map_field.cpp
index b119b506dc36..35192c81bd90 100644
--- a/src/map_field.cpp
+++ b/src/map_field.cpp
@@ -1377,12 +1377,9 @@ void map::player_in_field( player &u )
                     } else {
                         // Lying in the fire is BAAAD news, hits every body part.
                         msg_num = 3;
-                        const std::vector<bodypart_id> &all_parts = u.get_all_body_parts();
-                        // HACK: Skip num_bp part
-                        for( auto bp : all_parts ) {
-                            if( bp->token != num_bp ) {
-                                parts_burned.push_back( bp );
-                            }
+                        const auto &all_bps = u.get_all_body_parts( true );
+                        for( const auto &bp : all_bps ) {
+                            parts_burned.emplace_back( bp );
                         }
                     }
 
@@ -1656,7 +1653,7 @@ void map::monster_in_field( monster &z )
         const field_type_id cur_field_type = cur.get_field_type();
         if( cur_field_type == fd_web ) {
             if( !z.has_flag( MF_WEBWALK ) ) {
-                z.add_effect( effect_webbed, 1_turns, num_bp, cur.get_field_intensity() );
+                z.add_effect( effect_webbed, 1_turns, bodypart_str_id::NULL_ID(), cur.get_field_intensity() );
                 cur.set_field_intensity( 0 );
             }
         }
diff --git a/src/mattack_actors.cpp b/src/mattack_actors.cpp
index a70f031bba4f..9234b133e15e 100644
--- a/src/mattack_actors.cpp
+++ b/src/mattack_actors.cpp
@@ -325,7 +325,7 @@ bool melee_actor::call( monster &z ) const
 
     target->on_hit( &z, bp_hit.id() );
     dealt_damage_instance dealt_damage = target->deal_damage( &z, bp_hit.id(), damage );
-    dealt_damage.bp_hit = bp_hit->token;
+    dealt_damage.bp_hit = bp_hit;
 
     int damage_total = dealt_damage.total_damage();
     add_msg( m_debug, "%s's melee_attack did %d damage", z.name(), damage_total );
@@ -351,13 +351,13 @@ void melee_actor::on_damage( monster &z, Creature &target, dealt_damage_instance
         sfx::do_player_death_hurt( dynamic_cast<player &>( target ), false );
     }
     auto msg_type = target.attitude_to( g->u ) == Attitude::A_FRIENDLY ? m_bad : m_neutral;
-    const body_part bp = dealt.bp_hit;
+    const bodypart_str_id bp = dealt.bp_hit;
     target.add_msg_player_or_npc( msg_type, hit_dmg_u, hit_dmg_npc, z.name(),
                                   body_part_name_accusative( bp ) );
 
     for( const auto &eff : effects ) {
         if( x_in_y( eff.chance, 100 ) ) {
-            const bodypart_str_id &affected_bp = convert_bp( eff.affect_hit_bp ? bp : eff.bp );
+            const bodypart_str_id &affected_bp = eff.affect_hit_bp ? bp : convert_bp( eff.bp );
             target.add_effect( eff.id, time_duration::from_turns( eff.duration ), affected_bp );
             if( eff.permanent ) {
                 target.get_effect( eff.id, affected_bp ).set_permanent();
@@ -383,7 +383,7 @@ void bite_actor::on_damage( monster &z, Creature &target, dealt_damage_instance
 {
     melee_actor::on_damage( z, target, dealt );
     if( target.has_effect( effect_grabbed ) && one_in( no_infection_chance - dealt.total_damage() ) ) {
-        const bodypart_str_id hit = convert_bp( dealt.bp_hit );
+        const bodypart_str_id &hit = dealt.bp_hit;
         if( target.has_effect( effect_bite, hit ) ) {
             target.add_effect( effect_bite, 40_minutes, hit );
         } else if( target.has_effect( effect_infected, hit ) ) {
diff --git a/src/melee.cpp b/src/melee.cpp
index b89cac9d93ec..bbb975fe29c0 100644
--- a/src/melee.cpp
+++ b/src/melee.cpp
@@ -653,7 +653,7 @@ void Character::melee_attack( Creature &t, bool allow_special, const matec_id *f
     check_dead_state();
     if( t.as_character() ) {
         dealt_projectile_attack dp = dealt_projectile_attack();
-        t.as_character()->on_hit( this, bodypart_id( "num_bp" ), &dp );
+        t.as_character()->on_hit( this, bodypart_str_id::NULL_ID().id(), &dp );
     }
     return;
 }
diff --git a/src/monattack.cpp b/src/monattack.cpp
index daa542060ba2..761a323b2393 100644
--- a/src/monattack.cpp
+++ b/src/monattack.cpp
@@ -1421,21 +1421,21 @@ bool mattack::science( monster *const z ) // I said SCIENCE again!
     return true;
 }
 
-static body_part body_part_hit_by_plant()
+static bodypart_str_id body_part_hit_by_plant()
 {
-    body_part hit = num_bp;
+    bodypart_str_id hit;
     if( one_in( 2 ) ) {
-        hit = bp_leg_l;
+        hit = body_part_leg_l;
     } else {
-        hit = bp_leg_r;
+        hit = body_part_leg_r;
     }
     if( one_in( 4 ) ) {
-        hit = bp_torso;
+        hit = body_part_torso;
     } else if( one_in( 2 ) ) {
         if( one_in( 2 ) ) {
-            hit = bp_foot_l;
+            hit = body_part_foot_l;
         } else {
-            hit = bp_foot_r;
+            hit = body_part_foot_r;
         }
     }
     return hit;
@@ -1483,14 +1483,14 @@ bool mattack::growplants( monster *z )
             continue;
         }
 
-        const body_part hit = body_part_hit_by_plant();
+        const bodypart_str_id hit = body_part_hit_by_plant();
         critter->add_msg_player_or_npc( m_bad,
                                         //~ %s is bodypart name in accusative.
                                         _( "A tree bursts forth from the earth and pierces your %s!" ),
                                         //~ %s is bodypart name in accusative.
                                         _( "A tree bursts forth from the earth and pierces <npcname>'s %s!" ),
                                         body_part_name_accusative( hit ) );
-        critter->deal_damage( z, convert_bp( hit ).id(), damage_instance( DT_STAB, rng( 10, 30 ) ) );
+        critter->deal_damage( z, hit.id(), damage_instance( DT_STAB, rng( 10, 30 ) ) );
     }
 
     // 1 in 5 chance of making existing vegetation grow larger
@@ -1518,14 +1518,14 @@ bool mattack::growplants( monster *z )
             // Underbrush => young tree
             g->m.ter_set( p, t_tree_young );
             if( critter != nullptr && !critter->uncanny_dodge() ) {
-                const body_part hit = body_part_hit_by_plant();
+                const bodypart_str_id hit = body_part_hit_by_plant();
                 critter->add_msg_player_or_npc( m_bad,
                                                 //~ %s is bodypart name in accusative.
                                                 _( "The underbrush beneath your feet grows and pierces your %s!" ),
                                                 //~ %s is bodypart name in accusative.
                                                 _( "Underbrush grows into a tree, and it pierces <npcname>'s %s!" ),
                                                 body_part_name_accusative( hit ) );
-                critter->deal_damage( z, convert_bp( hit ).id(), damage_instance( DT_STAB, rng( 10, 30 ) ) );
+                critter->deal_damage( z, hit.id(), damage_instance( DT_STAB, rng( 10, 30 ) ) );
             }
         }
     }
@@ -2088,11 +2088,11 @@ bool mattack::fungus_fortify( monster *z )
         // Aimed at the player, too?  Sure!
         const tripoint hit_pos = target->pos() + point( rng( -1, 1 ), rng( -1, 1 ) );
         if( hit_pos == target->pos() && !target->uncanny_dodge() ) {
-            const body_part hit = body_part_hit_by_plant();
+            const bodypart_str_id hit = body_part_hit_by_plant();
             //~ %s is bodypart name in accusative.
             add_msg( m_bad, _( "A fungal tendril bursts forth from the earth and pierces your %s!" ),
                      body_part_name_accusative( hit ) );
-            g->u.deal_damage( z, convert_bp( hit ).id(), damage_instance( DT_CUT, rng( 5, 11 ) ) );
+            g->u.deal_damage( z, hit.id(), damage_instance( DT_CUT, rng( 5, 11 ) ) );
             g->u.check_dead_state();
             // Probably doesn't have spores available *just* yet.  Let's be nice.
         } else if( monster *const tendril = g->place_critter_at( mon_fungal_tendril, hit_pos ) ) {
@@ -2501,7 +2501,7 @@ bool mattack::callblobs( monster *z )
         }
         ( *ally )->set_dest( post );
         if( !( *ally )->has_effect( effect_ai_controlled ) ) {
-            ( *ally )->add_effect( effect_ai_controlled, 1_turns, num_bp );
+            ( *ally )->add_effect( effect_ai_controlled, 1_turns );
         }
     }
     // This is telepathy, doesn't take any moves.
@@ -2537,7 +2537,7 @@ bool mattack::jackson( monster *z )
         }
         ( *ally )->set_dest( post );
         if( !( *ally )->has_effect( effect_ai_controlled ) ) {
-            ( *ally )->add_effect( effect_ai_controlled, 1_turns, num_bp );
+            ( *ally )->add_effect( effect_ai_controlled, 1_turns );
         }
     }
     // Did we convert anybody?
@@ -3185,7 +3185,7 @@ bool mattack::nurse_operate( monster *z )
             // Check if we successfully grabbed the target
             if( target->has_effect( effect_grabbed ) ) {
                 z->dragged_foe_id = target->getID();
-                z->add_effect( effect_dragging, 1_turns, num_bp );
+                z->add_effect( effect_dragging, 1_turns );
                 return true;
             }
         }
@@ -5386,11 +5386,11 @@ bool mattack::bio_op_takedown( monster *z )
         return true;
     }
     // Yes, it has the CQC bionic.
-    bodypart_id hit( "num_bp" );
+    bodypart_str_id hit;
     if( one_in( 2 ) ) {
-        hit = bodypart_id( "leg_l" );
+        hit = body_part_leg_l;
     } else {
-        hit = bodypart_id( "leg_r" );
+        hit = body_part_leg_r;
     }
     // Weak kick to start with, knocks you off your footing
 
@@ -5403,17 +5403,17 @@ bool mattack::bio_op_takedown( monster *z )
     if( !foe->is_throw_immune() ) {
         if( !target->is_immune_effect( effect_downed ) ) {
             if( one_in( 4 ) ) {
-                hit = bodypart_id( "head" );
+                hit = body_part_head;
                 // 50% damage buff for the headshot.
                 dam = rng( 9, 21 );
                 target->add_msg_if_player( m_bad, _( "and slams you, face first, to the ground for %d damage!" ),
                                            dam );
-                foe->deal_damage( z, bodypart_id( "head" ), damage_instance( DT_BASH, dam ) );
+                foe->deal_damage( z, body_part_head.id(), damage_instance( DT_BASH, dam ) );
             } else {
-                hit = bodypart_id( "torso" );
+                hit = body_part_torso;
                 dam = rng( 6, 18 );
                 target->add_msg_if_player( m_bad, _( "and slams you to the ground for %d damage!" ), dam );
-                foe->deal_damage( z, bodypart_id( "torso" ), damage_instance( DT_BASH, dam ) );
+                foe->deal_damage( z, body_part_torso.id(), damage_instance( DT_BASH, dam ) );
             }
             foe->add_effect( effect_downed, 3_turns );
         }
@@ -5421,12 +5421,12 @@ bool mattack::bio_op_takedown( monster *z )
                  foe->martial_arts_data->selected_has_weapon( foe->primary_weapon().typeId() ) ) &&
                !thrown_by_judo( z ) ) {
         // Saved by the tentacle-bracing! :)
-        hit = bodypart_id( "torso" );
+        hit = body_part_torso;
         dam = rng( 3, 9 );
         target->add_msg_if_player( m_bad, _( "and slams you for %d damage!" ), dam );
         foe->deal_damage( z, bodypart_id( "torso" ), damage_instance( DT_BASH, dam ) );
     }
-    target->on_hit( z, hit );
+    target->on_hit( z, hit.id() );
     foe->check_dead_state();
 
     return true;
@@ -5982,7 +5982,7 @@ bool mattack::zombie_fuse( monster *z )
                  z->name() );
     }
     z->moves -= 200;
-    z->add_effect( effect_grown_of_fuse, 10_days, num_bp,
+    z->add_effect( effect_grown_of_fuse, 10_days, bodypart_str_id::NULL_ID(),
                    critter->get_hp_max() + z->get_effect( effect_grown_of_fuse ).get_intensity() );
     z->heal( critter->get_hp(), true );
     critter->death_drops = false;
diff --git a/src/mondeath.cpp b/src/mondeath.cpp
index 954c5e87f385..245803edddb6 100644
--- a/src/mondeath.cpp
+++ b/src/mondeath.cpp
@@ -864,7 +864,7 @@ void mdeath::detonate( monster &z )
         }
     }
     // HACK, used to stop them from having ammo on respawn
-    z.add_effect( effect_no_ammo, 1_turns, num_bp );
+    z.add_effect( effect_no_ammo, 1_turns );
 
     // First die normally
     mdeath::normal( z );
diff --git a/src/monexamine.cpp b/src/monexamine.cpp
index 016959764076..a40583a84367 100644
--- a/src/monexamine.cpp
+++ b/src/monexamine.cpp
@@ -454,7 +454,7 @@ bool monexamine::mech_hack( monster &z )
         if( query_yn( _( "Swipe your %s into the %s's security port?" ), item::nname( card_type ),
                       z.get_name() ) ) {
             you.mod_moves( -100 );
-            z.add_effect( effect_pet, 1_turns, num_bp );
+            z.add_effect( effect_pet, 1_turns );
             z.friendly = -1;
             if( z.has_flag( MF_RIDEABLE_MECH ) ) {
                 add_msg( m_good, _( "The %s whirs into life and opens its restraints to accept a pilot." ),
@@ -513,7 +513,7 @@ bool monexamine::pay_bot( monster &z )
                 time_duration time_bought = time_duration::from_minutes( amount );
                 you.use_charges( itype_cash_card, amount * 10 );
                 z.add_effect( effect_pet, time_bought );
-                z.add_effect( effect_paid, time_bought, num_bp );
+                z.add_effect( effect_paid, time_bought );
                 z.friendly = -1;
                 popup( _( "Your friendship grows stronger!\n This %s will follow you for %s." ), z.get_name(),
                        to_string( z.get_effect_dur( effect_pet ) ) );
@@ -599,7 +599,7 @@ void monexamine::attach_or_remove_saddle( monster &z )
             add_msg( _( "Never mind." ) );
             return;
         }
-        z.add_effect( effect_saddled, 1_turns, num_bp );
+        z.add_effect( effect_saddled, 1_turns );
         z.set_tack_item( loc->detach() );
     }
 }
@@ -669,7 +669,7 @@ void monexamine::attach_bag_to( monster &z )
     item &it = *loc;
     z.set_storage_item( it.detach( ) );
     add_msg( _( "You mount the %1$s on your %2$s." ), it.display_name(), pet_name );
-    z.add_effect( effect_has_bag, 1_turns, num_bp );
+    z.add_effect( effect_has_bag, 1_turns );
     // Update encumbrance in case we were wearing it
     you.flag_encumbrance();
     you.moves -= 200;
@@ -798,7 +798,7 @@ bool monexamine::add_armor( monster &z )
     z.set_armor_item( loc->detach() );
     add_msg( pgettext( "pet armor", "You put the %1$s on your %2$s." ), armor.display_name(),
              pet_name );
-    z.add_effect( effect_monster_armor, 1_turns, num_bp );
+    z.add_effect( effect_monster_armor, 1_turns );
     // TODO: armoring a horse takes a lot longer than 2 seconds. This should be a long action.
     get_avatar().moves -= 200;
     return true;
@@ -1001,7 +1001,7 @@ void monexamine::milk_source( monster &source_mon )
         // pin the cow in place if it isn't already
         bool temp_tie = !source_mon.has_effect( effect_tied );
         if( temp_tie ) {
-            source_mon.add_effect( effect_tied, 1_turns, num_bp );
+            source_mon.add_effect( effect_tied, 1_turns );
             you.activity->str_values.emplace_back( "temp_tie" );
         }
         add_msg( _( "You milk the %s." ), source_mon.get_name() );
diff --git a/src/monmove.cpp b/src/monmove.cpp
index 7d46668a13d6..b526d5c79d98 100644
--- a/src/monmove.cpp
+++ b/src/monmove.cpp
@@ -1713,13 +1713,13 @@ bool monster::move_to( const tripoint &p, bool force, bool step_on_critter,
     }
 
     if( g->m.has_flag( "UNSTABLE", destination ) && on_ground ) {
-        add_effect( effect_bouldering, 1_turns, num_bp );
+        add_effect( effect_bouldering, 1_turns );
     } else if( has_effect( effect_bouldering ) ) {
         remove_effect( effect_bouldering );
     }
 
     if( g->m.has_flag_ter_or_furn( TFLAG_NO_SIGHT, destination ) && on_ground ) {
-        add_effect( effect_no_sight, 1_turns, num_bp );
+        add_effect( effect_no_sight, 1_turns );
     } else if( has_effect( effect_no_sight ) ) {
         remove_effect( effect_no_sight );
     }
diff --git a/src/monster.cpp b/src/monster.cpp
index 1b7abba0880e..fb98bf9bcce0 100644
--- a/src/monster.cpp
+++ b/src/monster.cpp
@@ -1747,7 +1747,7 @@ void monster::melee_attack( Creature &target, float accuracy )
     if( hitspread >= 0 ) {
         target.deal_melee_hit( this, hitspread, false, damage, dealt_dam );
     }
-    body_part bp_hit = dealt_dam.bp_hit;
+    const bodypart_str_id bp_hit = dealt_dam.bp_hit;
 
     const int total_dealt = dealt_dam.total_damage();
     if( hitspread < 0 ) {
@@ -1774,7 +1774,7 @@ void monster::melee_attack( Creature &target, float accuracy )
                 sfx::do_player_death_hurt( dynamic_cast<player &>( target ), false );
                 //~ 1$s is attacker name, 2$s is bodypart name in accusative.
                 add_msg( m_bad, _( "%1$s hits your %2$s." ), disp_name( false, true ),
-                         body_part_name_accusative( bp_hit ) );
+                         bp_hit->accusative.translated() );
             } else if( target.is_npc() ) {
                 if( has_effect( effect_ridden ) && has_flag( MF_RIDEABLE_MECH ) && pos() == g->u.pos() ) {
                     //~ %1$s: name of your mount, %2$s: target NPC name, %3$d: damage value
@@ -1784,7 +1784,7 @@ void monster::melee_attack( Creature &target, float accuracy )
                     //~ %1$s: attacker name, %2$s: target NPC name, %3$s: bodypart name in accusative
                     add_msg( _( "%1$s hits %2$s %3$s." ), disp_name( false, true ),
                              target.disp_name( true ),
-                             body_part_name_accusative( bp_hit ) );
+                             bp_hit->accusative.translated() );
                 }
             } else {
                 if( has_effect( effect_ridden ) && has_flag( MF_RIDEABLE_MECH ) && pos() == g->u.pos() ) {
@@ -1799,7 +1799,7 @@ void monster::melee_attack( Creature &target, float accuracy )
         } else if( target.is_player() ) {
             //~ %s is bodypart name in accusative.
             add_msg( m_bad, _( "Something hits your %s." ),
-                     body_part_name_accusative( bp_hit ) );
+                     bp_hit->accusative.translated() );
         }
     } else {
         // No damage dealt
@@ -1807,14 +1807,14 @@ void monster::melee_attack( Creature &target, float accuracy )
             if( target.is_player() ) {
                 //~ 1$s is attacker name, 2$s is bodypart name in accusative, 3$s is armor name
                 add_msg( _( "%1$s hits your %2$s, but your %3$s protects you." ), disp_name( false, true ),
-                         body_part_name_accusative( bp_hit ), target.skin_name() );
+                         bp_hit->accusative.translated(), target.skin_name() );
             } else if( target.is_npc() ) {
                 //~ $1s is monster name, %2$s is that monster target name,
                 //~ $3s is target bodypart name in accusative, $4s is the monster target name,
                 //~ 5$s is target armor name.
                 add_msg( _( "%1$s hits %2$s %3$s but is stopped by %4$s %5$s." ), disp_name( false, true ),
                          target.disp_name( true ),
-                         body_part_name_accusative( bp_hit ),
+                         bp_hit->accusative.translated(),
                          target.disp_name( true ),
                          target.skin_name() );
             } else {
@@ -1828,7 +1828,7 @@ void monster::melee_attack( Creature &target, float accuracy )
         } else if( target.is_player() ) {
             //~ 1$s is bodypart name in accusative, 2$s is armor name.
             add_msg( _( "Something hits your %1$s, but your %2$s protects you." ),
-                     body_part_name_accusative( bp_hit ), target.skin_name() );
+                     bp_hit->accusative.translated(), target.skin_name() );
         }
     }
 
@@ -1848,10 +1848,10 @@ void monster::melee_attack( Creature &target, float accuracy )
     // Add any on damage effects
     for( const auto &eff : type->atk_effs ) {
         if( x_in_y( eff.chance, 100 ) ) {
-            const body_part affected_bp = eff.affect_hit_bp ? bp_hit : eff.bp;
-            target.add_effect( eff.id, time_duration::from_turns( eff.duration ), convert_bp( affected_bp ) );
+            const bodypart_str_id &affected_bp = eff.affect_hit_bp ? bp_hit : convert_bp( eff.bp );
+            target.add_effect( eff.id, time_duration::from_turns( eff.duration ), affected_bp );
             if( eff.permanent ) {
-                target.get_effect( eff.id, convert_bp( affected_bp ) ).set_permanent();
+                target.get_effect( eff.id, affected_bp ).set_permanent();
             }
         }
     }
@@ -1876,7 +1876,7 @@ void monster::melee_attack( Creature &target, float accuracy )
 
     if( total_dealt > 6 && stab_cut > 0 && has_flag( MF_BLEED ) ) {
         // Maybe should only be if DT_CUT > 6... Balance question
-        target.add_effect( effect_bleed, 6_minutes, convert_bp( bp_hit ) );
+        target.add_effect( effect_bleed, 6_minutes, bp_hit );
     }
 }
 
@@ -2119,16 +2119,13 @@ bool monster::move_effects( bool )
     return true;
 }
 
-void monster::add_effect( const efftype_id &eff_id, const time_duration &dur,
-                          const bodypart_str_id &,
-                          int intensity, bool force, bool deferred )
+void monster::add_effect( const efftype_id &eff_id, const time_duration &dur )
 {
-    // Effects are not applied to specific monster body part
-    Creature::add_effect( eff_id, dur, bodypart_str_id::NULL_ID(), intensity, force, deferred );
+    Creature::add_effect( eff_id, dur, bodypart_str_id::NULL_ID() );
 }
 
 void monster::add_effect( const efftype_id &eff_id, const time_duration &dur,
-                          body_part,
+                          const bodypart_str_id &,
                           int intensity, bool force, bool deferred )
 {
     // Effects are not applied to specific monster body part
@@ -2979,7 +2976,7 @@ void monster::make_pet()
 {
     friendly = -1;
     g->critter_tracker->update_faction( *this );
-    add_effect( effect_pet, 1_turns, num_bp );
+    add_effect( effect_pet, 1_turns );
 }
 
 bool monster::is_pet() const
diff --git a/src/monster.h b/src/monster.h
index ff7831893a13..18d6cb72e161 100644
--- a/src/monster.h
+++ b/src/monster.h
@@ -370,8 +370,10 @@ class monster : public Creature, public location_visitable<monster>
         /** Performs any monster-specific modifications to the arguments before passing to Creature::add_effect(). */
         void add_effect( const efftype_id &eff_id, const time_duration &dur, const bodypart_str_id &bp,
                          int intensity = 0, bool force = false, bool deferred = false ) override;
-        void add_effect( const efftype_id &eff_id, const time_duration &dur, body_part bp = num_bp,
-                         int intensity = 0, bool force = false, bool deferred = false );
+        void add_effect( const efftype_id &eff_id, const time_duration &dur );
+        // Use the bodypart_str_id variant instead
+        void add_effect( const efftype_id &eff_id, const time_duration &dur, body_part bp,
+                         int intensity = 0, bool force = false, bool deferred = false ) = delete;
         /** Returns a std::string containing effects for descriptions */
         std::string get_effect_status() const;
 
diff --git a/src/panels.cpp b/src/panels.cpp
index 4f9dec354a40..e26cd1023cfc 100644
--- a/src/panels.cpp
+++ b/src/panels.cpp
@@ -826,7 +826,7 @@ static void draw_limb2( avatar &u, const catacurses::window &w )
         } else {
             wmove( w, point( 11, i / 2 ) );
         }
-        wprintz( w, u.limb_color( bp, true, true, true ), str );
+        wprintz( w, u.limb_color( bp.id(), true, true, true ), str );
         if( i % 2 == 0 ) {
             wmove( w, point( 5, i / 2 ) );
         } else {
@@ -1140,7 +1140,7 @@ static void draw_limb_narrow( avatar &u, const catacurses::window &w )
         std::string str = body_part_hp_bar_ui_text( bp );
         wmove( w, point( nx, ny ) );
         str = left_justify( str, 5 );
-        wprintz( w, u.limb_color( bp, true, true, true ), str + ":" );
+        wprintz( w, u.limb_color( bp.id(), true, true, true ), str + ":" );
     }
     wnoutrefresh( w );
 }
@@ -1576,7 +1576,7 @@ static void draw_health_classic( avatar &u, const catacurses::window &w )
     for( const bodypart_id &bp : u.get_all_body_parts( true ) ) {
         const std::string str = body_part_hp_bar_ui_text( part[i] );
         wmove( w, point( 8, i ) );
-        wprintz( w, u.limb_color( part[i], true, true, true ), str );
+        wprintz( w, u.limb_color( part[i].id(), true, true, true ), str );
         wmove( w, point( 14, i ) );
         draw_limb_health( u, w, bp.id() );
         i++;
diff --git a/src/suffer.cpp b/src/suffer.cpp
index 92e2574b92c3..6db2b391bf64 100644
--- a/src/suffer.cpp
+++ b/src/suffer.cpp
@@ -893,7 +893,7 @@ std::map<bodypart_id, float> Character::bodypart_exposure()
         // What body parts does this item cover?
         body_part_set covered = it->get_covered_body_parts();
         for( const bodypart_id &bp : all_body_parts )  {
-            if( bp->token != num_bp && !covered.test( bp.id() ) ) {
+            if( bp.id() && !covered.test( bp.id() ) ) {
                 continue;
             }
             // How much exposure does this item leave on this part? (1.0 == naked)
diff --git a/src/trapfunc.cpp b/src/trapfunc.cpp
index 6f63e9103544..c7e985fd8b6c 100644
--- a/src/trapfunc.cpp
+++ b/src/trapfunc.cpp
@@ -336,22 +336,22 @@ bool trapfunc::crossbow( const tripoint &p, Creature *c, item * )
         if( n != nullptr ) {
             ///\EFFECT_DODGE reduces chance of being hit by crossbow trap
             if( !one_in( 4 ) && rng( 8, 20 ) > n->get_dodge() ) {
-                bodypart_id hit = bodypart_id( " num_bp" );
+                bodypart_str_id hit;
                 switch( rng( 1, 10 ) ) {
                     case  1:
                         if( one_in( 2 ) ) {
-                            hit = bodypart_id( "foot_l" );
+                            hit = body_part_foot_l;
                         } else {
-                            hit = bodypart_id( "foot_r" );
+                            hit = body_part_foot_r;
                         }
                         break;
                     case  2:
                     case  3:
                     case  4:
                         if( one_in( 2 ) ) {
-                            hit = bodypart_id( "leg_l" );
+                            hit = body_part_leg_l;
                         } else {
-                            hit = bodypart_id( "leg_r" );
+                            hit = body_part_leg_r;
                         }
                         break;
                     case  5:
@@ -359,10 +359,10 @@ bool trapfunc::crossbow( const tripoint &p, Creature *c, item * )
                     case  7:
                     case  8:
                     case  9:
-                        hit = bodypart_id( "torso" );
+                        hit = body_part_torso;
                         break;
                     case 10:
-                        hit = bodypart_id( "head" );
+                        hit = body_part_head;
                         break;
                 }
                 //~ %s is bodypart
@@ -400,7 +400,7 @@ bool trapfunc::crossbow( const tripoint &p, Creature *c, item * )
                 if( seen ) {
                     add_msg( m_bad, _( "A bolt shoots out and hits the %s!" ), z->name() );
                 }
-                z->deal_damage( nullptr, bodypart_id( "torso" ), damage_instance( DT_STAB, rng( 30, 45 ) ) );
+                z->deal_damage( nullptr, body_part_torso.id(), damage_instance( DT_STAB, rng( 30, 45 ) ) );
                 add_bolt = !one_in( 10 );
             } else if( seen ) {
                 add_msg( m_neutral, _( "A bolt shoots out, but misses the %s." ), z->name() );
@@ -432,22 +432,22 @@ bool trapfunc::shotgun( const tripoint &p, Creature *c, item * )
         if( n != nullptr ) {
             ///\EFFECT_DODGE reduces chance of being hit by shotgun trap
             if( rng( 5, 50 ) > n->get_dodge() ) {
-                bodypart_id hit = bodypart_id( "num_bp" );
+                bodypart_str_id hit;
                 switch( rng( 1, 10 ) ) {
                     case  1:
                         if( one_in( 2 ) ) {
-                            hit = bodypart_id( "foot_l" );
+                            hit = body_part_foot_l;
                         } else {
-                            hit = bodypart_id( "foot_r" );
+                            hit = body_part_foot_r;
                         }
                         break;
                     case  2:
                     case  3:
                     case  4:
                         if( one_in( 2 ) ) {
-                            hit = bodypart_id( "leg_l" );
+                            hit = body_part_leg_l;
                         } else {
-                            hit = bodypart_id( "leg_r" );
+                            hit = body_part_leg_r;
                         }
                         break;
                     case  5:
@@ -455,10 +455,10 @@ bool trapfunc::shotgun( const tripoint &p, Creature *c, item * )
                     case  7:
                     case  8:
                     case  9:
-                        hit = bodypart_id( "torso" );
+                        hit = body_part_torso;
                         break;
                     case 10:
-                        hit = bodypart_id( "head" );
+                        hit = body_part_head;
                         break;
                 }
                 //~ %s is bodypart
@@ -478,10 +478,10 @@ bool trapfunc::shotgun( const tripoint &p, Creature *c, item * )
                 add_msg( m_bad, _( "A shotgun fires and hits the %s!" ), z->name() );
             }
             if( shots > 1 ) {
-                z->deal_damage( nullptr, bodypart_id( "torso" ), damage_instance( DT_BULLET, rng( 60,
+                z->deal_damage( nullptr, body_part_torso.id(), damage_instance( DT_BULLET, rng( 60,
                                 80 ), 0, 1.5f ) );
             }
-            z->deal_damage( nullptr, bodypart_id( "torso" ), damage_instance( DT_BULLET, rng( 60,
+            z->deal_damage( nullptr, body_part_torso.id(), damage_instance( DT_BULLET, rng( 60,
                             80 ), 0, 1.5f ) );
         }
         c->check_dead_state();
@@ -823,19 +823,19 @@ bool trapfunc::pit_spikes( const tripoint &p, Creature *c, item * )
         } else if( 0 == damage || rng( 5, 30 ) < dodge ) {
             n->add_msg_if_player( _( "You avoid the spikes within." ) );
         } else {
-            bodypart_id hit( "num_bp" );
+            bodypart_str_id hit;
             switch( rng( 1, 10 ) ) {
                 case  1:
-                    hit = bodypart_id( "leg_l" );
+                    hit = body_part_leg_l;
                     break;
                 case  2:
-                    hit = bodypart_id( "leg_r" );
+                    hit = body_part_leg_r;
                     break;
                 case  3:
-                    hit = bodypart_id( "arm_l" );
+                    hit = body_part_arm_l;
                     break;
                 case  4:
-                    hit = bodypart_id( "arm_r" );
+                    hit = body_part_arm_r;
                     break;
                 case  5:
                 case  6:
@@ -843,7 +843,7 @@ bool trapfunc::pit_spikes( const tripoint &p, Creature *c, item * )
                 case  8:
                 case  9:
                 case 10:
-                    hit = bodypart_id( "torso" );
+                    hit = body_part_torso;
                     break;
             }
             n->add_msg_if_player( m_bad, _( "The spikes impale your %s!" ),
@@ -855,7 +855,7 @@ bool trapfunc::pit_spikes( const tripoint &p, Creature *c, item * )
             add_msg( m_bad, _( "Your %s falls into a pit!" ), z->get_name() );
             g->u.forced_dismount();
         }
-        z->deal_damage( nullptr, bodypart_id( "torso" ), damage_instance( DT_CUT, rng( 20, 50 ) ) );
+        z->deal_damage( nullptr, body_part_torso.id(), damage_instance( DT_CUT, rng( 20, 50 ) ) );
     }
     c->check_dead_state();
     if( one_in( 4 ) ) {
@@ -904,31 +904,31 @@ bool trapfunc::pit_glass( const tripoint &p, Creature *c, item * )
         } else if( 0 == damage || rng( 5, 30 ) < dodge ) {
             n->add_msg_if_player( _( "You avoid the glass shards within." ) );
         } else {
-            bodypart_id hit( " num_bp" );
+            bodypart_str_id hit;
             switch( rng( 1, 10 ) ) {
                 case  1:
-                    hit = bodypart_id( "leg_l" );
+                    hit = body_part_leg_l;
                     break;
                 case  2:
-                    hit = bodypart_id( "leg_r" );
+                    hit = body_part_leg_r;
                     break;
                 case  3:
-                    hit = bodypart_id( "arm_l" );
+                    hit = body_part_arm_l;
                     break;
                 case  4:
-                    hit = bodypart_id( "arm_r" );
+                    hit = body_part_arm_r;
                     break;
                 case  5:
-                    hit = bodypart_id( "foot_l" );
+                    hit = body_part_foot_l;
                     break;
                 case  6:
-                    hit = bodypart_id( "foot_r" );
+                    hit = body_part_foot_r;
                     break;
                 case  7:
                 case  8:
                 case  9:
                 case 10:
-                    hit = bodypart_id( "torso" );
+                    hit = body_part_torso;
                     break;
             }
             n->add_msg_if_player( m_bad, _( "The glass shards slash your %s!" ),
@@ -940,7 +940,7 @@ bool trapfunc::pit_glass( const tripoint &p, Creature *c, item * )
             add_msg( m_bad, _( "Your %s falls into a pit!" ), z->get_name() );
             g->u.forced_dismount();
         }
-        z->deal_damage( nullptr, bodypart_id( "torso" ), damage_instance( DT_CUT, rng( 20, 50 ) ) );
+        z->deal_damage( nullptr, body_part_torso.id(), damage_instance( DT_CUT, rng( 20, 50 ) ) );
     }
     c->check_dead_state();
     if( one_in( 5 ) ) {
diff --git a/src/weather.cpp b/src/weather.cpp
index 080f073403c2..2d6735fd8cd7 100644
--- a/src/weather.cpp
+++ b/src/weather.cpp
@@ -389,16 +389,16 @@ void weather_effect::wet_player( int amount )
         return;
     }
     std::map<bodypart_id, std::vector<const item *>> clothing_map;
-    for( const bodypart_id &bp : target.get_all_body_parts() ) {
+    const auto &all_bps = target.get_all_body_parts();
+    for( const bodypart_id &bp : all_bps ) {
         clothing_map.emplace( bp, std::vector<const item *>() );
     }
     for( const item * const &it : target.worn ) {
         // TODO: Port body part set id changes
         const body_part_set &covered = it->get_covered_body_parts();
-        for( size_t i = 0; i < num_bp; i++ ) {
-            body_part token = static_cast<body_part>( i );
-            if( covered.test( convert_bp( token ) ) ) {
-                clothing_map[convert_bp( token )].emplace_back( it );
+        for( const bodypart_id &bp : all_bps ) {
+            if( covered.test( bp.id() ) ) {
+                clothing_map[bp.id()].emplace_back( it );
             }
         }
     }
diff --git a/tests/encumbrance_test.cpp b/tests/encumbrance_test.cpp
index 24465ea93e8d..a7fb84ef128e 100644
--- a/tests/encumbrance_test.cpp
+++ b/tests/encumbrance_test.cpp
@@ -22,7 +22,7 @@
 static void test_encumbrance_on(
     player &p,
     std::vector<detached_ptr<item>> &clothing,
-    const std::string &body_part,
+    const bodypart_str_id &body_part,
     int expected_encumbrance,
     const std::function<void( player & )> &tweak_player = {}
 )
@@ -38,13 +38,13 @@ static void test_encumbrance_on(
         p.worn.push_back( std::move( i ) );
     }
     p.reset_encumbrance();
-    encumbrance_data enc = p.get_encumbrance().elems[ get_body_part_token( body_part ) ];
+    encumbrance_data enc = p.get_encumbrance().elems[ body_part ];
     CHECK( enc.encumbrance == expected_encumbrance );
 }
 
 static void test_encumbrance_items(
     std::vector<detached_ptr<item>> &clothing,
-    const std::string &body_part,
+    const bodypart_str_id &body_part,
     const int expected_encumbrance,
     const std::function<void( player & )> &tweak_player = {}
 )
@@ -62,7 +62,7 @@ static void test_encumbrance_items(
 
 static void test_encumbrance(
     const std::vector<std::string> &clothing_types,
-    const std::string &body_part,
+    const bodypart_str_id &body_part,
     const int expected_encumbrance
 )
 {
@@ -92,21 +92,21 @@ static constexpr int greatcoat_e = 23;
 TEST_CASE( "regular_clothing_encumbrance", "[encumbrance]" )
 {
     clear_all_state();
-    test_encumbrance( { "karate_gi" }, "TORSO", karate_gi_e );
-    test_encumbrance( { "vest" }, "TORSO", vest_e );
-    test_encumbrance( { "greatcoat" }, "TORSO", greatcoat_e );
+    test_encumbrance( { "karate_gi" }, body_part_torso, karate_gi_e );
+    test_encumbrance( { "vest" }, body_part_torso, vest_e );
+    test_encumbrance( { "greatcoat" }, body_part_torso, greatcoat_e );
 }
 
 TEST_CASE( "separate_layer_encumbrance", "[encumbrance]" )
 {
     clear_all_state();
-    test_encumbrance( { "vest", "greatcoat" }, "TORSO", vest_e + greatcoat_e );
+    test_encumbrance( { "vest", "greatcoat" }, body_part_torso, vest_e + greatcoat_e );
 }
 
 TEST_CASE( "out_of_order_encumbrance", "[encumbrance]" )
 {
     clear_all_state();
-    test_encumbrance( { "greatcoat", "vest" }, "TORSO", vest_e * 2 + greatcoat_e );
+    test_encumbrance( { "greatcoat", "vest" }, body_part_torso, vest_e * 2 + greatcoat_e );
 }
 
 TEST_CASE( "same_layer_encumbrance", "[encumbrance]" )
@@ -114,11 +114,11 @@ TEST_CASE( "same_layer_encumbrance", "[encumbrance]" )
     clear_all_state();
     // When stacking within a layer, encumbrance for additional items is
     // counted twice
-    test_encumbrance( { "vest", "vest" }, "TORSO", vest_e * 2 + vest_e );
+    test_encumbrance( { "vest", "vest" }, body_part_torso, vest_e * 2 + vest_e );
     // ... with a minimum of 2
-    test_encumbrance( { "karate_gi", "karate_gi" }, "TORSO", karate_gi_e * 2 + 2 );
+    test_encumbrance( { "karate_gi", "karate_gi" }, body_part_torso, karate_gi_e * 2 + 2 );
     // ... and a maximum of 10
-    test_encumbrance( { "greatcoat", "greatcoat" }, "TORSO", greatcoat_e * 2 + 10 );
+    test_encumbrance( { "greatcoat", "greatcoat" }, body_part_torso, greatcoat_e * 2 + 10 );
 }
 
 TEST_CASE( "tiny_clothing", "[encumbrance]" )
@@ -128,7 +128,7 @@ TEST_CASE( "tiny_clothing", "[encumbrance]" )
     i->set_flag( flag_id( "UNDERSIZE" ) );
     std::vector<detached_ptr<item>> items;
     items.push_back( std::move( i ) );
-    test_encumbrance_items( items, "TORSO",
+    test_encumbrance_items( items, body_part_torso,
                             vest_e * 3 );
 }
 
@@ -140,13 +140,13 @@ TEST_CASE( "tiny_character", "[encumbrance]" )
     std::vector<detached_ptr<item>> items;
     items.push_back( std::move( i ) );
     SECTION( "regular shirt" ) {
-        test_encumbrance_items( items, "TORSO",
+        test_encumbrance_items( items, body_part_torso,
                                 vest_e * 2,
                                 add_trait( "SMALL2" ) );
     }
     SECTION( "undersize shrt" ) {
         obj.set_flag( flag_id( "UNDERSIZE" ) );
-        test_encumbrance_items( items, "TORSO", vest_e,
+        test_encumbrance_items( items, body_part_torso, vest_e,
                                 add_trait( "SMALL2" ) );
     }
 }