diff --git a/src/battle_interface.c b/src/battle_interface.c
index c554863c5..bc6ff1122 100644
--- a/src/battle_interface.c
+++ b/src/battle_interface.c
@@ -172,9 +172,6 @@ extern const u16 gBattleInterface_BallStatusBarPal[];
 extern const u16 gBattleInterface_BallDisplayPal[];
 extern const u8 gHealthboxElementsGfxTable[][32];
 
-// functions
-extern void LoadBattleBarGfx(u8 arg0);
-
 // this file's functions
 
 static const u8 *GetHealthboxElementGfxPtr(u8 elementId);
diff --git a/src/battle_main.c b/src/battle_main.c
index c1dfde8c3..3c4a61600 100644
--- a/src/battle_main.c
+++ b/src/battle_main.c
@@ -7,6 +7,7 @@
 #include "scanline_effect.h"
 #include "battle_setup.h"
 #include "battle_scripts.h"
+#include "battle_interface.h"
 #include "pokemon.h"
 #include "palette.h"
 #include "task.h"
@@ -46,6 +47,8 @@
 #include "constants/battle_string_ids.h"
 #include "data2.h"
 #include "decompress.h"
+#include "international_string_util.h"
+#include "pokeball.h"
 
 struct UnknownPokemonStruct2
 {
@@ -107,17 +110,11 @@ extern const u8 gText_Confusion[];
 extern const u8 gText_Love[];
 
 // functions
-extern void ScanlineEffect_Clear(void);
-extern void sub_80356D0(void);
 extern void GetFrontierTrainerName(u8* dst, u16 trainerId); // battle tower
 extern void sub_8166188(void); // battle tower, sets link battle mons level but why?
 extern void sub_8165B88(u8* dst, u16 trainerId); // battle tower, gets language
-extern void PadNameString(u8* dst, u8 arg2); //
 extern void sub_81B9150(void);
-extern void sub_800AC34(void);
 extern void sub_80B3AF8(u8 taskId); // cable club
-extern void sub_8076918(u8 battlerId);
-extern void SetHealthboxSpriteVisible(u8 healthoxSpriteId);
 extern void sub_81A56B4(void); // battle frontier 2
 extern u8 sub_81A9E28(void); // battle frontier 2
 extern void sub_81A56E8(u8 battlerId); // battle frontier 2
diff --git a/src/battle_message.c b/src/battle_message.c
index ff608b6c5..2b9783f1a 100644
--- a/src/battle_message.c
+++ b/src/battle_message.c
@@ -13,6 +13,9 @@
 #include "palette.h"
 #include "battle_controllers.h"
 #include "battle_setup.h"
+#include "menu.h"
+#include "recorded_battle.h"
+#include "international_string_util.h"
 
 extern u8 gBattlerAbilities[MAX_BATTLERS_COUNT];
 extern u8 gUnknown_0203C7B4;
@@ -41,9 +44,6 @@ extern void GetEreaderTrainerName(u8 *txtPtr);
 extern void sub_81A36D0(u8 arg0, u16 trainerId); // battle_frontier_2
 extern void sub_81D572C(u8 arg0, u16 trainerId); // pokenav
 extern void GetFrontierTrainerName(u8 *dst, u16 trainerId);
-extern s32 GetStringCenterAlignXOffsetWithLetterSpacing(u8 fontId, const u8 *str, s32 totalWidth, s16 letterSpacing);
-extern u8 GetTextSpeedInRecordedBattle(void);
-extern u8 GetPlayerTextSpeed(void);
 
 // this file's functions
 static void sub_814F8F8(u8 *textPtr);
diff --git a/src/battle_script_commands.c b/src/battle_script_commands.c
index e8f2a5508..4d40d83a8 100644
--- a/src/battle_script_commands.c
+++ b/src/battle_script_commands.c
@@ -81,7 +81,6 @@ extern u16 GetBattlePyramidPickupItemId(void);
 extern u8 sav1_map_get_light_level(void);
 extern u8 sub_813B21C(void);
 extern u16 get_unknown_box_id(void);
-extern void sub_80356D0(void);
 
 // strings
 extern const u8 gText_BattleYesNoChoice[];
diff --git a/src/battle_setup.c b/src/battle_setup.c
index 81600cab7..52ed99b21 100644
--- a/src/battle_setup.c
+++ b/src/battle_setup.c
@@ -31,6 +31,7 @@
 #include "secret_base.h"
 #include "string_util.h"
 #include "overworld.h"
+#include "field_weather.h"
 
 enum
 {
@@ -60,14 +61,11 @@ extern void sub_81BE72C(void);
 extern void FreezeMapObjects(void);
 extern void sub_808BCF4(void);
 extern void sub_80EECC8(void);
-extern void c2_exit_to_overworld_1_continue_scripts_restart_music(void);
-extern void c2_exit_to_overworld_2_switch(void);
 extern void Overworld_ClearSavedMusic(void);
 extern void CB2_WhiteOut(void);
 extern void sub_80AF6F0(void);
 extern void PlayBattleBGM(void);
 extern void sub_81DA57C(void);
-extern u8 GetSav1Weather(void);
 extern u8 Overworld_GetFlashLevel(void);
 extern u16 sub_81A9AA8(u8 localId);
 extern u16 sub_81D6180(u8 localId);
@@ -84,8 +82,6 @@ extern void sub_80982B8(void);
 extern void sub_81A9EDC(u16 a0);
 extern void sub_81D572C(u8 a0, u16 arg1);
 
-extern void (*gFieldCallback)(void);
-
 // this file's functions
 static void DoBattlePikeWildBattle(void);
 static void DoSafariBattle(void);
diff --git a/src/battle_transition.c b/src/battle_transition.c
index bb7a02f41..e0d208f23 100644
--- a/src/battle_transition.c
+++ b/src/battle_transition.c
@@ -61,7 +61,6 @@ extern u16 gBattle_BG0_Y;
 
 extern const struct OamData gFieldObjectBaseOam_32x32;
 
-extern void c2_exit_to_overworld_2_switch(void);
 extern void sub_80AC3D0(void);
 
 // this file's functions
diff --git a/src/reshow_battle_screen.c b/src/reshow_battle_screen.c
index 1a7792e36..b12917c61 100644
--- a/src/reshow_battle_screen.c
+++ b/src/reshow_battle_screen.c
@@ -26,9 +26,6 @@ extern struct SpriteTemplate gUnknown_0202499C;
 
 extern const union AnimCmd * const * const gMonAnimationsSpriteAnimsPtrTable[];
 
-extern void sub_8035658(void);
-extern u8 GetSubstituteSpriteDefault_Y(u8 bank);
-extern u8 sub_80A82E4(u8 bank);
 extern void sub_806A068(u16 species, u8 bankIdentity);
 extern void sub_806A12C(u16 backPicId, u8 bankIdentity);