diff --git a/src/units/unit.cpp b/src/units/unit.cpp
index 8bfbab55916c0..4883b373432c2 100644
--- a/src/units/unit.cpp
+++ b/src/units/unit.cpp
@@ -1482,19 +1482,35 @@ static bool matches_ability_filter(const config & cfg, const std::string& tag_na
 	if(!string_matches_if_present(filter, cfg, "active_on", "both"))
 		return false;
 
-	if(!int_matches_if_present(filter, cfg, "value"))
-		return false;
+	if(!filter["value"].empty()){
+		if(tag_name == "drains" || tag_name == "berserk" || tag_name != "heal_on_hit"){
+			int def = 0;
+			if(tag_name == "drains"){
+				def = 25;
+			}
+			if(tag_name == "berserk"){
+				def = 1;
+			}
+			if(!int_matches_if_present(filter, cfg, "value" , def)){
+				return false;
+			}
+		} else if(cfg["value"].empty()){
+			return false;
+		}
+		if(!int_matches_if_present(filter, cfg, "value"))
+			return false;
+	}
 
-	if(!int_matches_if_present_or_negative(filter, cfg, "add", "sub"))
+	if((!filter["add"].empty() && (cfg["add"].empty() && cfg["sub"].empty()) || !int_matches_if_present_or_negative(filter, cfg, "add", "sub")))
 		return false;
 
-	if(!int_matches_if_present_or_negative(filter, cfg, "sub", "add"))
+	if((!filter["sub"].empty() && (cfg["add"].empty() && cfg["sub"].empty()) || !int_matches_if_present_or_negative(filter, cfg, "sub", "add")))
 		return false;
 
-	if(!double_matches_if_present(filter, cfg, "multiply"))
+	if(!filter["multiply"].empty() && (cfg["multiply"].empty() || !double_matches_if_present(filter, cfg, "multiply")))
 		return false;
 
-	if(!double_matches_if_present(filter, cfg, "divide"))
+	if(!filter["divide"].empty() && (cfg["divide"].empty() || !double_matches_if_present(filter, cfg, "divide")))
 		return false;
 
 	if(!type_value_if_present(filter, cfg))
diff --git a/src/utils/config_filters.cpp b/src/utils/config_filters.cpp
index df7e8faa3b704..d4438e1867843 100644
--- a/src/utils/config_filters.cpp
+++ b/src/utils/config_filters.cpp
@@ -50,13 +50,13 @@ bool utils::config_filters::unsigned_matches_if_present(const config& filter, co
 	return in_ranges<int>(cfg[attribute].to_int(0), utils::parse_ranges_unsigned(filter[attribute].str()));
 }
 
-bool utils::config_filters::int_matches_if_present(const config& filter, const config& cfg, const std::string& attribute)
+bool utils::config_filters::int_matches_if_present(const config& filter, const config& cfg, const std::string& attribute, int def)
 {
 	if(filter[attribute].empty()) {
 		return true;
 	}
 
-	return in_ranges<int>(cfg[attribute].to_int(0), utils::parse_ranges_int(filter[attribute].str()));
+	return in_ranges<int>(cfg[attribute].to_int(def), utils::parse_ranges_int(filter[attribute].str()));
 }
 
 bool utils::config_filters::int_matches_if_present_or_negative(
diff --git a/src/utils/config_filters.hpp b/src/utils/config_filters.hpp
index ba65e3d25fa72..d5e1644eb62c8 100644
--- a/src/utils/config_filters.hpp
+++ b/src/utils/config_filters.hpp
@@ -35,7 +35,7 @@ namespace utils::config_filters
 bool bool_matches_if_present(const config& filter, const config& cfg, const std::string& attribute, bool def);
 
 bool double_matches_if_present(const config& filter, const config& cfg, const std::string& attribute);
-bool int_matches_if_present(const config& filter, const config& cfg, const std::string& attribute);
+bool int_matches_if_present(const config& filter, const config& cfg, const std::string& attribute, int def = 0);
 
 /**
  * Restricts filters to only looking for values that are zero or more.