diff --git a/Data/CommonEvents.rxdata b/Data/CommonEvents.rxdata
index 0fdb778d1..d7b68454f 100644
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diff --git a/Data/Map058.rxdata b/Data/Map058.rxdata
index 711dd6c4a..2a5b7f1ab 100644
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diff --git a/Data/Map077.rxdata b/Data/Map077.rxdata
index 37ae20604..cb04f1718 100644
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diff --git a/Data/Map160.rxdata b/Data/Map160.rxdata
index ad8f27e97..295a116bb 100644
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diff --git a/Data/Map295.rxdata b/Data/Map295.rxdata
index 5b4ea64d5..56bcb78eb 100644
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diff --git a/Data/Map551.rxdata b/Data/Map551.rxdata
index 768d926cd..7140d8beb 100644
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diff --git a/Data/Map552.rxdata b/Data/Map552.rxdata
index 234197652..9591a2a8f 100644
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diff --git a/Data/Map593.rxdata b/Data/Map593.rxdata
index e217804d9..eca5a417c 100644
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diff --git a/Data/Map659.rxdata b/Data/Map659.rxdata
index bcb897f91..206f341d0 100644
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diff --git a/Data/MapInfos.rxdata b/Data/MapInfos.rxdata
index 261775b02..4530007fd 100644
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diff --git a/Data/Scripts/010_Data/002_PBS data/013_Trainer.rb b/Data/Scripts/010_Data/002_PBS data/013_Trainer.rb
index 1ffd8697a..858e082ba 100644
--- a/Data/Scripts/010_Data/002_PBS data/013_Trainer.rb	
+++ b/Data/Scripts/010_Data/002_PBS data/013_Trainer.rb	
@@ -140,6 +140,9 @@ module GameData
         if placeholder_species.include?(species)
           species = replace_species_with_placeholder(species)
         end
+        if $game_switches[REVERSED_MODE]
+          species = reverseFusionSpecies(species)
+        end
         level =pkmn_data[:level]
         if $game_switches[Settings::OVERRIDE_BATTLE_LEVEL_SWITCH]
           override_level = $game_variables[Settings::OVERRIDE_BATTLE_LEVEL_VALUE_VAR]
diff --git a/Data/Scripts/049_Compatibility/Constants.rb b/Data/Scripts/049_Compatibility/Constants.rb
index dadd367b2..84fd7a5f6 100644
--- a/Data/Scripts/049_Compatibility/Constants.rb
+++ b/Data/Scripts/049_Compatibility/Constants.rb
@@ -1,6 +1,9 @@
 #Switches
 NEW_GAME_PLUS = 972
 BEAT_MT_SILVER = 918
+REVERSED_MODE = 47
+GAME_DIFFICULTY_EASY = 665
+GAME_DIFFICULTY_HARD = 666
 
 GOT_BADGE_1 = 4
 GOT_BADGE_2 = 5
diff --git a/Data/Scripts/050_AddOns/GeneralUtils.rb b/Data/Scripts/050_AddOns/GeneralUtils.rb
index 49f2fdd33..b69dcd123 100644
--- a/Data/Scripts/050_AddOns/GeneralUtils.rb
+++ b/Data/Scripts/050_AddOns/GeneralUtils.rb
@@ -356,5 +356,15 @@ def getArceusPlateType(heldItem)
   end
 end
 
+def reverseFusionSpecies(species)
+  dexId = getDexNumberForSpecies(species)
+  return species if dexId <= NB_POKEMON
+  return species if dexId > (NB_POKEMON * NB_POKEMON) + NB_POKEMON
+  body = getBasePokemonID(dexId, true)
+  head = getBasePokemonID(dexId, false)
+  newspecies = (head) * NB_POKEMON + body
+  return getPokemon(newspecies)
+end
+
 
 
diff --git a/Data/System.rxdata b/Data/System.rxdata
index 05ddfd55d..af29bcf33 100644
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