diff --git a/Data/Scripts/001_Technical/002_RubyUtilities.rb b/Data/Scripts/001_Technical/002_RubyUtilities.rb
index 6646b17c1..0e1426fd5 100644
--- a/Data/Scripts/001_Technical/002_RubyUtilities.rb
+++ b/Data/Scripts/001_Technical/002_RubyUtilities.rb
@@ -2,7 +2,7 @@
 # class Object
 #===============================================================================
 class Object
-  alias full_inspect inspect
+  alias full_inspect inspect unless method_defined?(:full_inspect)
 
   def inspect
     return "#<#{self.class}>"
diff --git a/Data/Scripts/005_Sprites/008_Sprite_AnimationSprite.rb b/Data/Scripts/005_Sprites/008_Sprite_AnimationSprite.rb
index 16f577874..f6274c7b0 100644
--- a/Data/Scripts/005_Sprites/008_Sprite_AnimationSprite.rb
+++ b/Data/Scripts/005_Sprites/008_Sprite_AnimationSprite.rb
@@ -41,9 +41,9 @@ end
 
 
 class Spriteset_Map
-  alias _animationSprite_initialize initialize
-  alias _animationSprite_update update
-  alias _animationSprite_dispose dispose
+  alias _animationSprite_initialize initialize unless method_defined?(:_animationSprite_initialize)
+  alias _animationSprite_update update unless method_defined?(:_animationSprite_update)
+  alias _animationSprite_dispose dispose unless method_defined?(:_animationSprite_dispose)
 
   def initialize(map = nil)
     @usersprites = []
diff --git a/Data/Scripts/005_Sprites/009_Sprite_DynamicShadows.rb b/Data/Scripts/005_Sprites/009_Sprite_DynamicShadows.rb
index 45761a647..0f6d56eb8 100644
--- a/Data/Scripts/005_Sprites/009_Sprite_DynamicShadows.rb
+++ b/Data/Scripts/005_Sprites/009_Sprite_DynamicShadows.rb
@@ -123,7 +123,7 @@ end
 # ? CLASS Sprite_Character edit
 #===================================================
 class Sprite_Character < RPG::Sprite
-  alias shadow_initialize initialize
+  alias shadow_initialize initialize unless method_defined?(:shadow_initialize)
 
   def initialize(viewport, character = nil)
     @ombrelist = []
@@ -153,7 +153,7 @@ class Sprite_Character < RPG::Sprite
     @ombrelist.clear
   end
 
-  alias shadow_update update
+  alias shadow_update update unless method_defined?(:shadow_update)
 
   def update
     shadow_update
@@ -178,7 +178,8 @@ end
 class Spriteset_Map
   attr_accessor :shadows
 
-  alias shadow_initialize initialize
+  alias shadow_initialize initialize unless method_defined?(:shadow_initialize)
+
   def initialize(map = nil)
     @shadows = []
     warn = false
diff --git a/Data/Scripts/005_Sprites/010_ParticleEngine.rb b/Data/Scripts/005_Sprites/010_ParticleEngine.rb
index 2a7cc40ef..01037b8ed 100644
--- a/Data/Scripts/005_Sprites/010_ParticleEngine.rb
+++ b/Data/Scripts/005_Sprites/010_ParticleEngine.rb
@@ -566,7 +566,8 @@ end
 class Game_Event < Game_Character
   attr_accessor :pe_refresh
 
-  alias nf_particles_game_map_initialize initialize
+  alias nf_particles_game_map_initialize initialize unless method_defined?(:nf_particles_game_map_initialize)
+
   def initialize(map_id, event, map = nil)
     @pe_refresh = false
     begin
@@ -576,7 +577,8 @@ class Game_Event < Game_Character
     end
   end
 
-  alias nf_particles_game_map_refresh refresh
+  alias nf_particles_game_map_refresh refresh unless method_defined?(:nf_particles_game_map_refresh)
+
   def refresh
     nf_particles_game_map_refresh
     @pe_refresh = true
diff --git a/Data/Scripts/011_Battle/002_Battler/006_Battler_AbilityAndItem.rb b/Data/Scripts/011_Battle/002_Battler/006_Battler_AbilityAndItem.rb
index db098f44a..23199df64 100644
--- a/Data/Scripts/011_Battle/002_Battler/006_Battler_AbilityAndItem.rb
+++ b/Data/Scripts/011_Battle/002_Battler/006_Battler_AbilityAndItem.rb
@@ -236,7 +236,7 @@ class Battle::Battler
     return if fainted?
     return if self.item
     @battle.pbPriority(true).each do |b|
-      next if b.opposes?
+      next if b.opposes?(self)
       next if !b.hasActiveAbility?(:SYMBIOSIS)
       next if !b.item || b.unlosableItem?(b.item)
       next if unlosableItem?(b.item)
diff --git a/Data/Scripts/011_Battle/006_Other battle code/006_Battle_Clauses.rb b/Data/Scripts/011_Battle/006_Other battle code/006_Battle_Clauses.rb
index e4278bbe6..1bad500aa 100644
--- a/Data/Scripts/011_Battle/006_Other battle code/006_Battle_Clauses.rb	
+++ b/Data/Scripts/011_Battle/006_Other battle code/006_Battle_Clauses.rb	
@@ -103,7 +103,9 @@ end
 
 
 class Battle::Move::RaiseUserEvasion1   # Double Team
-  alias __clauses__pbMoveFailed? pbMoveFailed?
+  unless method_defined?(:__clauses__pbMoveFailed?)
+    alias __clauses__pbMoveFailed? pbMoveFailed?
+  end
 
   def pbMoveFailed?(user, targets)
     if !damagingMove? && @battle.rules["evasionclause"]
@@ -117,7 +119,9 @@ end
 
 
 class Battle::Move::RaiseUserEvasion2MinimizeUser   # Minimize
-  alias __clauses__pbMoveFailed? pbMoveFailed?
+  unless method_defined?(:__clauses__pbMoveFailed?)
+    alias __clauses__pbMoveFailed? pbMoveFailed?
+  end
 
   def pbMoveFailed?(user, targets)
     if !damagingMove? && @battle.rules["evasionclause"]
@@ -131,7 +135,9 @@ end
 
 
 class Battle::Move::UserTargetSwapAbilities   # Skill Swap
-  alias __clauses__pbFailsAgainstTarget? pbFailsAgainstTarget?
+  unless method_defined?(:__clauses__pbFailsAgainstTarget?)
+    alias __clauses__pbFailsAgainstTarget? pbFailsAgainstTarget?
+  end
 
   def pbFailsAgainstTarget?(user, target, show_message)
     if @battle.rules["skillswapclause"]
@@ -145,7 +151,9 @@ end
 
 
 class Battle::Move::FixedDamage20   # Sonic Boom
-  alias __clauses__pbFailsAgainstTarget? pbFailsAgainstTarget?
+  unless method_defined?(:__clauses__pbFailsAgainstTarget?)
+    alias __clauses__pbFailsAgainstTarget? pbFailsAgainstTarget?
+  end
 
   def pbFailsAgainstTarget?(user, target, show_message)
     if @battle.rules["sonicboomclause"]
@@ -159,7 +167,9 @@ end
 
 
 class Battle::Move::FixedDamage40   # Dragon Rage
-  alias __clauses__pbFailsAgainstTarget? pbFailsAgainstTarget?
+  unless method_defined?(:__clauses__pbFailsAgainstTarget?)
+    alias __clauses__pbFailsAgainstTarget? pbFailsAgainstTarget?
+  end
 
   def pbFailsAgainstTarget?(user, target, show_message)
     if @battle.rules["sonicboomclause"]
@@ -173,7 +183,9 @@ end
 
 
 class Battle::Move::OHKO
-  alias __clauses__pbFailsAgainstTarget? pbFailsAgainstTarget?
+  unless method_defined?(:__clauses__pbFailsAgainstTarget?)
+    alias __clauses__pbFailsAgainstTarget? pbFailsAgainstTarget?
+  end
 
   def pbFailsAgainstTarget?(user, target, show_message)
     if @battle.rules["ohkoclause"]
@@ -187,7 +199,9 @@ end
 
 
 class Battle::Move::OHKOIce
-  alias __clauses__pbFailsAgainstTarget? pbFailsAgainstTarget?
+  unless method_defined?(:__clauses__pbFailsAgainstTarget?)
+    alias __clauses__pbFailsAgainstTarget? pbFailsAgainstTarget?
+  end
 
   def pbFailsAgainstTarget?(user, target, show_message)
     if @battle.rules["ohkoclause"]
@@ -201,7 +215,9 @@ end
 
 
 class Battle::Move::OHKOHitsUndergroundTarget
-  alias __clauses__pbFailsAgainstTarget? pbFailsAgainstTarget?
+  unless method_defined?(:__clauses__pbFailsAgainstTarget?)
+    alias __clauses__pbFailsAgainstTarget? pbFailsAgainstTarget?
+  end
 
   def pbFailsAgainstTarget?(user, target, show_message)
     if @battle.rules["ohkoclause"]
@@ -215,9 +231,8 @@ end
 
 
 class Battle::Move::UserFaintsExplosive   # Self-Destruct
-  unless @__clauses__aliased
+  unless method_defined?(:__clauses__pbMoveFailed?)
     alias __clauses__pbMoveFailed? pbMoveFailed?
-    @__clauses__aliased = true
   end
 
   def pbMoveFailed?(user, targets)
@@ -247,7 +262,9 @@ end
 
 
 class Battle::Move::StartPerishCountsForAllBattlers   # Perish Song
-  alias __clauses__pbFailsAgainstTarget? pbFailsAgainstTarget?
+  unless method_defined?(:__clauses__pbFailsAgainstTarget?)
+    alias __clauses__pbFailsAgainstTarget? pbFailsAgainstTarget?
+  end
 
   def pbFailsAgainstTarget?(user, target, show_message)
     if @battle.rules["perishsongclause"] &&
@@ -262,7 +279,9 @@ end
 
 
 class Battle::Move::AttackerFaintsIfUserFaints   # Destiny Bond
-  alias __clauses__pbFailsAgainstTarget? pbFailsAgainstTarget?
+  unless method_defined?(:__clauses__pbFailsAgainstTarget?)
+    alias __clauses__pbFailsAgainstTarget? pbFailsAgainstTarget?
+  end
 
   def pbFailsAgainstTarget?(user, target, show_message)
     if @battle.rules["perishsongclause"] &&
diff --git a/Data/Scripts/011_Battle/007_Other battle types/001_SafariBattle.rb b/Data/Scripts/011_Battle/007_Other battle types/001_SafariBattle.rb
index bcff111af..407d51f16 100644
--- a/Data/Scripts/011_Battle/007_Other battle types/001_SafariBattle.rb	
+++ b/Data/Scripts/011_Battle/007_Other battle types/001_SafariBattle.rb	
@@ -272,7 +272,8 @@ class Battle::Scene
     rockAnim.dispose
   end
 
-  alias __safari__pbThrowSuccess pbThrowSuccess
+  alias __safari__pbThrowSuccess pbThrowSuccess unless method_defined?(:__safari__pbThrowSuccess)
+
   def pbThrowSuccess
     __safari__pbThrowSuccess
     pbWildBattleSuccess if @battle.is_a?(SafariBattle)
diff --git a/Data/Scripts/011_Battle/007_Other battle types/002_BugContestBattle.rb b/Data/Scripts/011_Battle/007_Other battle types/002_BugContestBattle.rb
index 4f71968d9..0c7b78483 100644
--- a/Data/Scripts/011_Battle/007_Other battle types/002_BugContestBattle.rb	
+++ b/Data/Scripts/011_Battle/007_Other battle types/002_BugContestBattle.rb	
@@ -2,7 +2,7 @@
 # Bug Catching Contest battle scene (the visuals of the battle)
 #===============================================================================
 class Battle::Scene
-  alias _bugContest_pbInitSprites pbInitSprites
+  alias _bugContest_pbInitSprites pbInitSprites unless method_defined?(:_bugContest_pbInitSprites)
 
   def pbInitSprites
     _bugContest_pbInitSprites
diff --git a/Data/Scripts/011_Battle/007_Other battle types/003_BattlePalaceBattle.rb b/Data/Scripts/011_Battle/007_Other battle types/003_BattlePalaceBattle.rb
index dfd310ed5..21488ac4e 100644
--- a/Data/Scripts/011_Battle/007_Other battle types/003_BattlePalaceBattle.rb	
+++ b/Data/Scripts/011_Battle/007_Other battle types/003_BattlePalaceBattle.rb	
@@ -172,14 +172,16 @@ end
 class Battle::AI
   attr_accessor :battlePalace
 
-  alias _battlePalace_initialize initialize
+  alias _battlePalace_initialize initialize unless method_defined?(:_battlePalace_initialize)
 
   def initialize(*arg)
     _battlePalace_initialize(*arg)
     @justswitched = [false, false, false, false]
   end
 
-  alias _battlePalace_pbEnemyShouldWithdraw? pbEnemyShouldWithdraw?
+  unless method_defined?(:_battlePalace_pbEnemyShouldWithdraw?)
+    alias _battlePalace_pbEnemyShouldWithdraw? pbEnemyShouldWithdraw?
+  end
 
   def pbEnemyShouldWithdraw?(idxBattler)
     return _battlePalace_pbEnemyShouldWithdraw?(idxBattler) if !@battlePalace
diff --git a/Data/Scripts/011_Battle/007_Other battle types/004_BattleArenaBattle.rb b/Data/Scripts/011_Battle/007_Other battle types/004_BattleArenaBattle.rb
index 82159ff48..de3285eae 100644
--- a/Data/Scripts/011_Battle/007_Other battle types/004_BattleArenaBattle.rb	
+++ b/Data/Scripts/011_Battle/007_Other battle types/004_BattleArenaBattle.rb	
@@ -211,7 +211,9 @@ end
 class Battle::AI
   attr_accessor :battleArena
 
-  alias _battleArena_pbEnemyShouldWithdraw? pbEnemyShouldWithdraw?
+  unless method_defined?(:_battleArena_pbEnemyShouldWithdraw?)
+    alias _battleArena_pbEnemyShouldWithdraw? pbEnemyShouldWithdraw?
+  end
 
   def pbEnemyShouldWithdraw?(idxBattler)
     return _battleArena_pbEnemyShouldWithdraw?(idxBattler) if !@battleArena
diff --git a/Data/Scripts/014_Pokemon/001_Pokemon-related/002_ShadowPokemon_Other.rb b/Data/Scripts/014_Pokemon/001_Pokemon-related/002_ShadowPokemon_Other.rb
index 0f49bc970..f92ffc558 100644
--- a/Data/Scripts/014_Pokemon/001_Pokemon-related/002_ShadowPokemon_Other.rb
+++ b/Data/Scripts/014_Pokemon/001_Pokemon-related/002_ShadowPokemon_Other.rb
@@ -169,7 +169,9 @@ end
 # Shadow Pokémon in battle.
 #===============================================================================
 class Battle
-  alias __shadow__pbCanUseItemOnPokemon? pbCanUseItemOnPokemon?
+  unless method_defined?(:__shadow__pbCanUseItemOnPokemon?)
+    alias __shadow__pbCanUseItemOnPokemon? pbCanUseItemOnPokemon?
+  end
 
   def pbCanUseItemOnPokemon?(item, pkmn, battler, scene, showMessages = true)
     ret = __shadow__pbCanUseItemOnPokemon?(item, pkmn, battler, scene, showMessages)
@@ -184,7 +186,7 @@ end
 
 
 class Battle::Battler
-  alias __shadow__pbInitPokemon pbInitPokemon
+  alias __shadow__pbInitPokemon pbInitPokemon unless method_defined?(:__shadow__pbInitPokemon)
 
   def pbInitPokemon(*arg)
     if self.pokemonIndex > 0 && inHyperMode?
diff --git a/Data/Scripts/014_Pokemon/003_Pokemon_ShadowPokemon.rb b/Data/Scripts/014_Pokemon/003_Pokemon_ShadowPokemon.rb
index 403e09e97..be9c2e263 100644
--- a/Data/Scripts/014_Pokemon/003_Pokemon_ShadowPokemon.rb
+++ b/Data/Scripts/014_Pokemon/003_Pokemon_ShadowPokemon.rb
@@ -10,7 +10,7 @@ class Pokemon
   attr_accessor :shadow_moves
   attr_accessor :heart_gauge_step_counter
 
-  alias __shadow_expeq exp=
+  alias __shadow_expeq exp= unless method_defined?(:__shadow_expeq)
   def exp=(value)
     if shadowPokemon?
       @saved_exp += value - @exp
@@ -19,7 +19,7 @@ class Pokemon
     end
   end
 
-  alias __shadow_hpeq hp=
+  alias __shadow_hpeq hp= unless method_defined?(:__shadow_hpeq)
   def hp=(value)
     __shadow_hpeq(value)
     @hyper_mode = false if @hp <= 0
@@ -107,7 +107,7 @@ class Pokemon
     return (self.heart_gauge == 0 || @hp == 0) ? false : @hyper_mode
   end
 
-  alias __shadow__changeHappiness changeHappiness
+  alias __shadow__changeHappiness changeHappiness unless method_defined?(:__shadow__changeHappiness)
   def changeHappiness(method)
     return if shadowPokemon? && heartStage >= 4
     __shadow__changeHappiness(method)
@@ -212,7 +212,7 @@ class Pokemon
     end
   end
 
-  alias __shadow_clone clone
+  alias __shadow_clone clone unless method_defined?(:__shadow_clone)
   def clone
     ret = __shadow_clone
     if @saved_ev
diff --git a/Data/Scripts/016_UI/022_UI_PurifyChamber.rb b/Data/Scripts/016_UI/022_UI_PurifyChamber.rb
index decba6c81..dada3c060 100644
--- a/Data/Scripts/016_UI/022_UI_PurifyChamber.rb
+++ b/Data/Scripts/016_UI/022_UI_PurifyChamber.rb
@@ -5,7 +5,7 @@ class Player < Trainer
   attr_accessor :has_snag_machine
   attr_accessor :seen_purify_chamber
 
-  alias __shadowPkmn__initialize initialize
+  alias __shadowPkmn__initialize initialize unless method_defined?(:__shadowPkmn__initialize)
   def initialize(name, trainer_type)
     __shadowPkmn__initialize(name, trainer_type)
     @has_snag_machine    = false