diff --git a/include/battle.h b/include/battle.h
index 5846321a62..a6e201a239 100644
--- a/include/battle.h
+++ b/include/battle.h
@@ -815,7 +815,7 @@ extern u16 gMoveToLearn;
 extern u8 gBattleMonForms[MAX_BATTLERS_COUNT];
 extern u32 gFieldStatuses;
 extern struct FieldTimer gFieldTimers;
-extern u16 gBattlerAbility;
+extern u8 gBattlerAbility;
 extern u16 gPartnerSpriteId;
 
 extern void (*gPreBattleCallback1)(void);
diff --git a/include/pokemon.h b/include/pokemon.h
index 8a8beb1063..0c64d21377 100644
--- a/include/pokemon.h
+++ b/include/pokemon.h
@@ -199,8 +199,11 @@ struct BaseStats
  /* 0x14 */ u8 eggGroup1;
  /* 0x15 */ u8 eggGroup2;
  /* 0x16 */ u16 abilities[2];
- /* 0x1A */ u8 safariZoneFleeRate;
- /* 0x1B */ u8 bodyColor : 7;
+#ifdef POKEMON_EXPANSION
+            u16 abilityHidden;
+#endif
+            u8 safariZoneFleeRate;
+            u8 bodyColor : 7;
             u8 noFlip : 1;
 };
 
diff --git a/src/battle_main.c b/src/battle_main.c
index f0c658773c..48129c5230 100644
--- a/src/battle_main.c
+++ b/src/battle_main.c
@@ -226,7 +226,7 @@ EWRAM_DATA u16 gMoveToLearn = 0;
 EWRAM_DATA u8 gBattleMonForms[MAX_BATTLERS_COUNT] = {0};
 EWRAM_DATA u32 gFieldStatuses = 0;
 EWRAM_DATA struct FieldTimer gFieldTimers = {0};
-EWRAM_DATA u16 gBattlerAbility = 0;
+EWRAM_DATA u8 gBattlerAbility = 0;
 EWRAM_DATA u16 gPartnerSpriteId = 0;
 
 // IWRAM common vars