diff --git a/asm/include/overlay_12_022378C0.inc b/asm/include/overlay_12_022378C0.inc
index 162e0e081..50dedd5d1 100644
--- a/asm/include/overlay_12_022378C0.inc
+++ b/asm/include/overlay_12_022378C0.inc
@@ -217,7 +217,7 @@
 .public BattleSystem_TryChangeForm
 .public ov12_0223B870
 .public ov12_0223BBF0
-.public ov12_0223BC48
+.public BattleSystem_HpBar_Init
 .public ov12_0223BCC8
 .public ov12_0223BD2C
 .public ov12_0223BD3C
@@ -238,7 +238,7 @@
 .public ov12_02258E7C
 .public ov12_02260EA4
 .public ov12_02261264
-.public ov12_0226127C
+.public OpponentData_GetHpBar
 .public ov12_022621C4
 .public ov12_02265FD4
 .public ov12_0226604C
diff --git a/asm/include/overlay_12_02264824.inc b/asm/include/overlay_12_02264824.inc
index 871dba6af..c8e8af171 100644
--- a/asm/include/overlay_12_02264824.inc
+++ b/asm/include/overlay_12_02264824.inc
@@ -58,7 +58,7 @@
 .public BattleSystem_GetPaletteData
 .public ov12_0223A9A4
 .public ov12_0226498C
-.public ov12_02264BCC
+.public BattleHpBar_LoadResources
 .public ov12_02264C68
 .public ov12_02264C84
 .public ov12_02264DCC
diff --git a/asm/include/overlay_12_battle_command.inc b/asm/include/overlay_12_battle_command.inc
index 5c1125506..3fae5b32b 100644
--- a/asm/include/overlay_12_battle_command.inc
+++ b/asm/include/overlay_12_battle_command.inc
@@ -143,7 +143,7 @@
 .public BattleSystem_GetTextFrameDelay
 .public ov12_0223B870
 .public ov12_0223BB1C
-.public ov12_0223BB28
+.public BattleSystem_GameStatIncrement
 .public ov12_0223BB44
 .public ov12_0223BBF0
 .public ov12_0223BCF0
diff --git a/asm/include/overlay_12_battle_controller_opponent.inc b/asm/include/overlay_12_battle_controller_opponent.inc
index b5b156db9..9793e9e55 100644
--- a/asm/include/overlay_12_battle_controller_opponent.inc
+++ b/asm/include/overlay_12_battle_controller_opponent.inc
@@ -195,7 +195,7 @@
 .public ov12_0223BAEC
 .public ov12_0223BB04
 .public ov12_0223BB10
-.public ov12_0223BB28
+.public BattleSystem_GameStatIncrement
 .public ov12_0223BB64
 .public ov12_0223BB6C
 .public ov12_0223BB78
@@ -205,7 +205,7 @@
 .public ov12_0223BBA8
 .public ov12_0223BBC0
 .public ov12_0223BBD8
-.public ov12_0223BC38
+.public BattleSystem_GetHpBar
 .public ov12_0223BC98
 .public ov12_0223BCC8
 .public BattleSystem_GetWinLoseFlags
@@ -248,7 +248,7 @@
 .public ov12_02261258
 .public ov12_02261264
 .public ov12_02261270
-.public ov12_0226127C
+.public OpponentData_GetHpBar
 .public ov12_02261280
 .public ov12_02261294
 .public ov12_02261FD4
diff --git a/asm/include/overlay_12_battle_system.inc b/asm/include/overlay_12_battle_system.inc
index 8f2fea031..b11a8c98b 100644
--- a/asm/include/overlay_12_battle_system.inc
+++ b/asm/include/overlay_12_battle_system.inc
@@ -146,7 +146,7 @@
 .public ov12_0223BB04
 .public ov12_0223BB10
 .public ov12_0223BB1C
-.public ov12_0223BB28
+.public BattleSystem_GameStatIncrement
 .public ov12_0223BB44
 .public ov12_0223BB64
 .public ov12_0223BB6C
@@ -163,8 +163,8 @@
 .public ov12_0223BC14
 .public ov12_0223BC20
 .public ov12_0223BC2C
-.public ov12_0223BC38
-.public ov12_0223BC48
+.public BattleSystem_GetHpBar
+.public BattleSystem_HpBar_Init
 .public ov12_0223BC98
 .public ov12_0223BCC8
 .public ov12_0223BCF0
@@ -211,8 +211,8 @@
 .public ov12_022582B8
 .public ov12_02261258
 .public ov12_02261270
-.public ov12_0226127C
-.public ov12_02264BCC
+.public OpponentData_GetHpBar
+.public BattleHpBar_LoadResources
 .public ov12_02264C68
 .public ov12_02264EE0
 .public ov12_02264F28
diff --git a/asm/overlay_12_022378C0.s b/asm/overlay_12_022378C0.s
index 5e673176a..244968eda 100644
--- a/asm/overlay_12_022378C0.s
+++ b/asm/overlay_12_022378C0.s
@@ -989,7 +989,7 @@ _02237FD8:
 	mov r2, #0xc0
 	bl sub_02009408
 	add r0, r4, #0
-	bl ov12_0223BC48
+	bl BattleSystem_HpBar_Init
 	bl ov12_022396F0
 	mov r0, #5
 	bl ov07_0221BEDC
@@ -3813,7 +3813,7 @@ _022398BE:
 	beq _022398FE
 _022398D6:
 	add r0, r7, #0
-	bl ov12_0226127C
+	bl OpponentData_GetHpBar
 	add r1, r0, #0
 	beq _022398FE
 	ldr r0, [r1, #0x28]
diff --git a/asm/overlay_12_battle_command.s b/asm/overlay_12_battle_command.s
index d81877f02..feb3743d5 100644
--- a/asm/overlay_12_battle_command.s
+++ b/asm/overlay_12_battle_command.s
@@ -2624,7 +2624,7 @@ _02246E2A:
 	bl SetMonData
 	ldr r0, [r4]
 	mov r1, #0x32
-	bl ov12_0223BB28
+	bl BattleSystem_GameStatIncrement
 _02246E5C:
 	add r0, r5, #0
 	bl sub_0208311C
diff --git a/asm/overlay_12_battle_controller_opponent.s b/asm/overlay_12_battle_controller_opponent.s
index 42fc94960..7a634d076 100644
--- a/asm/overlay_12_battle_controller_opponent.s
+++ b/asm/overlay_12_battle_controller_opponent.s
@@ -1809,7 +1809,7 @@ ov12_02259514: ; 0x02259514
 	cmp r1, r0
 	beq _02259586
 	add r0, r5, #0
-	bl ov12_0223BC38
+	bl BattleSystem_GetHpBar
 	bl ov12_02265D74
 _02259586:
 	add r0, r4, #0
@@ -1983,14 +1983,14 @@ ov12_022596B8: ; 0x022596B8
 	cmp r1, #0
 	bne _022596E4
 	ldrh r1, [r4, #2]
-	bl ov12_0223BB28
+	bl BattleSystem_GameStatIncrement
 	b _022596E4
 _022596D8:
 	ldrb r1, [r5, r1]
 	cmp r1, #0
 	beq _022596E4
 	ldrh r1, [r4, #2]
-	bl ov12_0223BB28
+	bl BattleSystem_GameStatIncrement
 _022596E4:
 	mov r1, #0x65
 	lsl r1, r1, #2
@@ -10528,7 +10528,7 @@ ov12_0225DAD4: ; 0x0225DAD4
 	cmp r1, r0
 	beq _0225DB16
 	ldr r0, [r4]
-	bl ov12_0223BC38
+	bl BattleSystem_GetHpBar
 	str r0, [sp, #8]
 	b _0225DB1A
 _0225DB16:
@@ -11423,7 +11423,7 @@ ov12_0225E250: ; 0x0225E250
 	cmp r1, r0
 	beq _0225E28A
 	ldr r0, [r4]
-	bl ov12_0223BC38
+	bl BattleSystem_GetHpBar
 	add r5, r0, #0
 	b _0225E28C
 _0225E28A:
@@ -11803,7 +11803,7 @@ ov12_0225E568: ; 0x0225E568
 	cmp r1, r0
 	beq _0225E5A2
 	ldr r0, [r4]
-	bl ov12_0223BC38
+	bl BattleSystem_GetHpBar
 	add r6, r0, #0
 	b _0225E5A4
 _0225E5A2:
@@ -13179,7 +13179,7 @@ _0225F070:
 	ldrb r7, [r0]
 	ldr r0, [r4]
 	add r1, r6, #0
-	bl ov12_0223BC38
+	bl BattleSystem_GetHpBar
 	mov r1, #0
 	mov r2, #1
 	add r5, r0, #0
@@ -13244,7 +13244,7 @@ _0225F10A:
 	ldr r1, [r1, #4]
 	ldrb r1, [r1, #0x11]
 	lsl r1, r1, #1
-	bl ov12_0223BC38
+	bl BattleSystem_GetHpBar
 	add r5, r0, #0
 	bl ov12_02264E00
 	mov r1, #0
@@ -13329,7 +13329,7 @@ _0225F1B2:
 	lsl r7, r0, #1
 	ldr r0, [r4]
 	add r1, r7, #0
-	bl ov12_0223BC38
+	bl BattleSystem_GetHpBar
 	str r0, [sp, #0x10]
 	ldr r0, [r4, #8]
 	add r1, r7, #0
@@ -14388,7 +14388,7 @@ ov12_0225FA44: ; 0x0225FA44
 	cmp r1, r0
 	beq _0225FA7E
 	ldr r0, [r4]
-	bl ov12_0223BC38
+	bl BattleSystem_GetHpBar
 	add r7, r0, #0
 	b _0225FA80
 _0225FA7E:
@@ -17416,11 +17416,11 @@ _02261278:
 	bx lr
 	thumb_func_end ov12_02261270
 
-	thumb_func_start ov12_0226127C
-ov12_0226127C: ; 0x0226127C
+	thumb_func_start OpponentData_GetHpBar
+OpponentData_GetHpBar: ; 0x0226127C
 	add r0, #0x28
 	bx lr
-	thumb_func_end ov12_0226127C
+	thumb_func_end OpponentData_GetHpBar
 
 	thumb_func_start ov12_02261280
 ov12_02261280: ; 0x02261280
diff --git a/asm/overlay_12_battle_system.s b/asm/overlay_12_battle_system.s
index 697cb67cb..214ddb0ff 100644
--- a/asm/overlay_12_battle_system.s
+++ b/asm/overlay_12_battle_system.s
@@ -6,325 +6,6 @@
 
 	.text
 
-	thumb_func_start ov12_0223BAD0
-ov12_0223BAD0: ; 0x0223BAD0
-	mov r1, #0x22
-	lsl r1, r1, #4
-	ldr r0, [r0, r1]
-	bx lr
-	thumb_func_end ov12_0223BAD0
-
-	thumb_func_start ov12_0223BAD8
-ov12_0223BAD8: ; 0x0223BAD8
-	mov r1, #0x89
-	lsl r1, r1, #2
-	ldr r0, [r0, r1]
-	bx lr
-	thumb_func_end ov12_0223BAD8
-
-	thumb_func_start ov12_0223BAE0
-ov12_0223BAE0: ; 0x0223BAE0
-	ldr r1, _0223BAE8 ; =0x00002228
-	add r0, r0, r1
-	bx lr
-	nop
-_0223BAE8: .word 0x00002228
-	thumb_func_end ov12_0223BAE0
-
-	thumb_func_start ov12_0223BAEC
-ov12_0223BAEC: ; 0x0223BAEC
-	ldr r1, _0223BAF4 ; =0x00002308
-	add r0, r0, r1
-	bx lr
-	nop
-_0223BAF4: .word 0x00002308
-	thumb_func_end ov12_0223BAEC
-
-	thumb_func_start BattleSystem_GetWeather
-BattleSystem_GetWeather: ; 0x0223BAF8
-	ldr r1, _0223BB00 ; =0x0000242C
-	ldr r0, [r0, r1]
-	bx lr
-	nop
-_0223BB00: .word 0x0000242C
-	thumb_func_end BattleSystem_GetWeather
-
-	thumb_func_start ov12_0223BB04
-ov12_0223BB04: ; 0x0223BB04
-	ldr r1, _0223BB0C ; =0x00002421
-	ldrb r0, [r0, r1]
-	bx lr
-	nop
-_0223BB0C: .word 0x00002421
-	thumb_func_end ov12_0223BB04
-
-	thumb_func_start ov12_0223BB10
-ov12_0223BB10: ; 0x0223BB10
-	ldr r2, _0223BB18 ; =0x00002421
-	strb r1, [r0, r2]
-	bx lr
-	nop
-_0223BB18: .word 0x00002421
-	thumb_func_end ov12_0223BB10
-
-	thumb_func_start ov12_0223BB1C
-ov12_0223BB1C: ; 0x0223BB1C
-	ldr r1, _0223BB24 ; =0x00002430
-	ldr r0, [r0, r1]
-	bx lr
-	nop
-_0223BB24: .word 0x00002430
-	thumb_func_end ov12_0223BB1C
-
-	thumb_func_start ov12_0223BB28
-ov12_0223BB28: ; 0x0223BB28
-	push {r3, lr}
-	ldr r2, _0223BB40 ; =0x0000240C
-	ldr r3, [r0, r2]
-	mov r2, #0x10
-	tst r2, r3
-	bne _0223BB3E
-	mov r2, #0x87
-	lsl r2, r2, #2
-	ldr r0, [r0, r2]
-	bl GameStats_Inc
-_0223BB3E:
-	pop {r3, pc}
-	.balign 4, 0
-_0223BB40: .word 0x0000240C
-	thumb_func_end ov12_0223BB28
-
-	thumb_func_start ov12_0223BB44
-ov12_0223BB44: ; 0x0223BB44
-	push {r3, lr}
-	ldr r1, _0223BB60 ; =0x0000240C
-	ldr r2, [r0, r1]
-	mov r1, #0x10
-	tst r1, r2
-	bne _0223BB5C
-	mov r1, #0x87
-	lsl r1, r1, #2
-	ldr r0, [r0, r1]
-	mov r1, #0x15
-	bl GameStats_AddSpecial
-_0223BB5C:
-	pop {r3, pc}
-	nop
-_0223BB60: .word 0x0000240C
-	thumb_func_end ov12_0223BB44
-
-	thumb_func_start ov12_0223BB64
-ov12_0223BB64: ; 0x0223BB64
-	mov r2, #0x91
-	lsl r2, r2, #6
-	str r1, [r0, r2]
-	bx lr
-	thumb_func_end ov12_0223BB64
-
-	thumb_func_start ov12_0223BB6C
-ov12_0223BB6C: ; 0x0223BB6C
-	ldr r2, _0223BB74 ; =0x00002444
-	strb r1, [r0, r2]
-	bx lr
-	nop
-_0223BB74: .word 0x00002444
-	thumb_func_end ov12_0223BB6C
-
-	thumb_func_start ov12_0223BB78
-ov12_0223BB78: ; 0x0223BB78
-	mov r1, #0x6f
-	lsl r1, r1, #2
-	ldr r0, [r0, r1]
-	bx lr
-	thumb_func_end ov12_0223BB78
-
-	thumb_func_start ov12_0223BB80
-ov12_0223BB80: ; 0x0223BB80
-	mov r2, #0x6f
-	lsl r2, r2, #2
-	str r1, [r0, r2]
-	bx lr
-	thumb_func_end ov12_0223BB80
-
-	thumb_func_start ov12_0223BB88
-ov12_0223BB88: ; 0x0223BB88
-	mov r2, #0x1d
-	lsl r2, r2, #4
-	add r2, r0, r2
-	lsl r0, r1, #4
-	add r0, r2, r0
-	bx lr
-	thumb_func_end ov12_0223BB88
-
-	thumb_func_start ov12_0223BB94
-ov12_0223BB94: ; 0x0223BB94
-	push {r3, r4, r5, lr}
-	add r5, r1, #0
-	add r4, r0, #0
-	cmp r5, #4
-	blt _0223BBA2
-	bl GF_AssertFail
-_0223BBA2:
-	lsl r0, r5, #4
-	ldr r0, [r4, r0]
-	pop {r3, r4, r5, pc}
-	thumb_func_end ov12_0223BB94
-
-	thumb_func_start ov12_0223BBA8
-ov12_0223BBA8: ; 0x0223BBA8
-	push {r4, r5, r6, lr}
-	add r4, r1, #0
-	add r5, r0, #0
-	add r6, r2, #0
-	cmp r4, #4
-	blt _0223BBB8
-	bl GF_AssertFail
-_0223BBB8:
-	lsl r0, r4, #4
-	add r0, r5, r0
-	str r6, [r0, #4]
-	pop {r4, r5, r6, pc}
-	thumb_func_end ov12_0223BBA8
-
-	thumb_func_start ov12_0223BBC0
-ov12_0223BBC0: ; 0x0223BBC0
-	push {r4, r5, r6, lr}
-	add r4, r1, #0
-	add r5, r0, #0
-	add r6, r2, #0
-	cmp r4, #4
-	blt _0223BBD0
-	bl GF_AssertFail
-_0223BBD0:
-	lsl r0, r4, #4
-	add r0, r5, r0
-	str r6, [r0, #8]
-	pop {r4, r5, r6, pc}
-	thumb_func_end ov12_0223BBC0
-
-	thumb_func_start ov12_0223BBD8
-ov12_0223BBD8: ; 0x0223BBD8
-	push {r4, r5, r6, lr}
-	add r4, r1, #0
-	add r5, r0, #0
-	add r6, r2, #0
-	cmp r4, #4
-	blt _0223BBE8
-	bl GF_AssertFail
-_0223BBE8:
-	lsl r0, r4, #4
-	add r0, r5, r0
-	str r6, [r0, #0xc]
-	pop {r4, r5, r6, pc}
-	thumb_func_end ov12_0223BBD8
-
-	thumb_func_start ov12_0223BBF0
-ov12_0223BBF0: ; 0x0223BBF0
-	ldr r2, _0223BBF8 ; =0x000023FD
-	strb r1, [r0, r2]
-	bx lr
-	nop
-_0223BBF8: .word 0x000023FD
-	thumb_func_end ov12_0223BBF0
-
-	thumb_func_start ov12_0223BBFC
-ov12_0223BBFC: ; 0x0223BBFC
-	ldr r2, _0223BC04 ; =0x000023F4
-	str r1, [r0, r2]
-	bx lr
-	nop
-_0223BC04: .word 0x000023F4
-	thumb_func_end ov12_0223BBFC
-
-	thumb_func_start ov12_0223BC08
-ov12_0223BC08: ; 0x0223BC08
-	ldr r2, _0223BC10 ; =0x000023F8
-	str r1, [r0, r2]
-	bx lr
-	nop
-_0223BC10: .word 0x000023F8
-	thumb_func_end ov12_0223BC08
-
-	thumb_func_start ov12_0223BC14
-ov12_0223BC14: ; 0x0223BC14
-	ldr r2, _0223BC1C ; =0x000023F4
-	ldr r0, [r0, r2]
-	strb r1, [r0]
-	bx lr
-	.balign 4, 0
-_0223BC1C: .word 0x000023F4
-	thumb_func_end ov12_0223BC14
-
-	thumb_func_start ov12_0223BC20
-ov12_0223BC20: ; 0x0223BC20
-	ldr r2, _0223BC28 ; =0x000023F8
-	ldr r0, [r0, r2]
-	strb r1, [r0]
-	bx lr
-	.balign 4, 0
-_0223BC28: .word 0x000023F8
-	thumb_func_end ov12_0223BC20
-
-	thumb_func_start ov12_0223BC2C
-ov12_0223BC2C: ; 0x0223BC2C
-	ldr r2, _0223BC34 ; =0x000023FE
-	strb r1, [r0, r2]
-	bx lr
-	nop
-_0223BC34: .word 0x000023FE
-	thumb_func_end ov12_0223BC2C
-
-	thumb_func_start ov12_0223BC38
-ov12_0223BC38: ; 0x0223BC38
-	lsl r1, r1, #2
-	add r0, r0, r1
-	ldr r3, _0223BC44 ; =ov12_0226127C
-	ldr r0, [r0, #0x34]
-	bx r3
-	nop
-_0223BC44: .word ov12_0226127C
-	thumb_func_end ov12_0223BC38
-
-	thumb_func_start ov12_0223BC48
-ov12_0223BC48: ; 0x0223BC48
-	push {r3, r4, r5, r6, r7, lr}
-	add r6, r0, #0
-	ldr r0, [r6, #0x44]
-	mov r7, #0
-	cmp r0, #0
-	ble _0223BC94
-	add r5, r6, #0
-_0223BC56:
-	ldr r0, [r5, #0x34]
-	bl ov12_0226127C
-	add r4, r0, #0
-	str r6, [r4, #0xc]
-	ldr r0, [r5, #0x34]
-	bl ov12_02261258
-	str r0, [sp]
-	add r0, r6, #0
-	bl BattleSystem_GetBattleType
-	add r1, r0, #0
-	ldr r0, [sp]
-	bl ov12_02265B64
-	add r1, r4, #0
-	add r1, #0x25
-	strb r0, [r1]
-	add r0, r4, #0
-	bl ov12_02264BCC
-	add r0, r4, #0
-	mov r1, #0
-	bl ov12_02264F28
-	ldr r0, [r6, #0x44]
-	add r7, r7, #1
-	add r5, r5, #4
-	cmp r7, r0
-	blt _0223BC56
-_0223BC94:
-	pop {r3, r4, r5, r6, r7, pc}
-	.balign 4, 0
-	thumb_func_end ov12_0223BC48
-
 	thumb_func_start ov12_0223BC98
 ov12_0223BC98: ; 0x0223BC98
 	push {r3, r4, r5, r6, r7, lr}
@@ -337,7 +18,7 @@ ov12_0223BC98: ; 0x0223BC98
 	mov r7, #1
 _0223BCA8:
 	ldr r0, [r5, #0x34]
-	bl ov12_0226127C
+	bl OpponentData_GetHpBar
 	ldr r1, [r0, #0x28]
 	cmp r1, #0
 	beq _0223BCBA
@@ -366,7 +47,7 @@ ov12_0223BCC8: ; 0x0223BCC8
 	add r7, r4, #0
 _0223BCD8:
 	ldr r0, [r5, #0x34]
-	bl ov12_0226127C
+	bl OpponentData_GetHpBar
 	add r1, r7, #0
 	bl ov12_02264F28
 	ldr r0, [r6, #0x44]
@@ -389,7 +70,7 @@ ov12_0223BCF0: ; 0x0223BCF0
 	add r5, r6, #0
 _0223BCFE:
 	ldr r0, [r5, #0x34]
-	bl ov12_0226127C
+	bl OpponentData_GetHpBar
 	bl ov12_02264C68
 	ldr r0, [r6, #0x44]
 	add r4, r4, #1
@@ -1156,7 +837,7 @@ ov12_0223C224: ; 0x0223C224
 	add r5, r6, #0
 _0223C234:
 	ldr r0, [r5, #0x34]
-	bl ov12_0226127C
+	bl OpponentData_GetHpBar
 	add r1, r7, #0
 	bl ov12_02264EE0
 	ldr r0, [r6, #0x44]
diff --git a/asm/overlay_12_02264824.s b/asm/overlay_12_hp_bar.s
similarity index 99%
rename from asm/overlay_12_02264824.s
rename to asm/overlay_12_hp_bar.s
index d51bccee7..2d8e1b7ba 100644
--- a/asm/overlay_12_02264824.s
+++ b/asm/overlay_12_hp_bar.s
@@ -484,8 +484,8 @@ _02264BC8:
 	.balign 4, 0
 	thumb_func_end ov12_02264B94
 
-	thumb_func_start ov12_02264BCC
-ov12_02264BCC: ; 0x02264BCC
+	thumb_func_start BattleHpBar_LoadResources
+BattleHpBar_LoadResources: ; 0x02264BCC
 	push {r4, r5, r6, r7, lr}
 	sub sp, #0xc
 	add r5, r0, #0
@@ -555,7 +555,7 @@ _02264C5A:
 	pop {r4, r5, r6, r7, pc}
 	.balign 4, 0
 _02264C64: .word ov12_0226D368
-	thumb_func_end ov12_02264BCC
+	thumb_func_end BattleHpBar_LoadResources
 
 	thumb_func_start ov12_02264C68
 ov12_02264C68: ; 0x02264C68
diff --git a/include/battle.h b/include/battle.h
index cfddd7d94..f4e7baea2 100644
--- a/include/battle.h
+++ b/include/battle.h
@@ -6,6 +6,7 @@
 #include "bg_window.h"
 #include "item.h"
 #include "font.h"
+#include "game_stats.h"
 #include "move.h"
 #include "options.h"
 #include "palette.h"
@@ -418,35 +419,38 @@ typedef struct BATTLECONTEXT {
 
 typedef struct BattleSystem BattleSystem;
 
-typedef struct OpponentData_UnkSub_28 {
-    u8 unk0;
-    u32 unk4;
-    u32 unk8;
+typedef struct BattleHpBar {
+    u8 script;
+    void *unk4;
+    void *unk8;
     BattleSystem *bsys;
-    u32 unk10;
-    u8 unk14;
-    u8 unk15;
-    u8 unk16;
-    u8 unk17;
-    int unk18;
-    int unk1C;
-    int unk20;
-    int unk24;
-    int unk28;
-    int unk2C;
-    int unk30;
-    int unk34;
-    u8 unk38;
-    u8 unk39;
-    u8 unk3A;
+    void *unk10;
+    s32 hp;
+    s32 maxHp;
+    s32 damage;
+    s32 hpCalc;
+    u8 battlerId;
+    u8 type;
+    u8 unk26;
+    u8 unk27;
+    s32 exp;
+    s32 maxExp;
+    s32 gainedExp;
+    s32 expCalc;
+    u8 level;
+    u8 gender;
+    u8 status;
     u8 unk3B;
     u8 unk3C;
     u8 unk3D;
     u8 unk3E;
-    u8 unk3F_0:1, unk3F_1:1, unk3F_2:1, unk3F_3:1;
-    u32 unk40;
+    u8 unk3F_0:1;
+    u8 unk3F_1:1;
+    u8 unk3F_2:1;
+    u8 unk3F_3:1;
+    void *unk40;
     u16 unk44;
-} OpponentData_UnkSub_28;
+} BattleHpBar;
 
 typedef struct OpponentData_UnkSub_70 {
     s8 unk0;
@@ -465,7 +469,7 @@ typedef struct OpponentData {
     u32 *unk1C;
     u32 *unk20;
     u32 *unk24;
-    OpponentData_UnkSub_28 unk28;
+    BattleHpBar hpBar;
     OpponentData_UnkSub_70 unk70;
     u32 unk78;
     u32 *unk7C;
@@ -506,10 +510,6 @@ typedef struct UnkBattleSystemSub220 {
     int unk8;
 } UnkBattleSystemSub220;
 
-typedef struct BattleSystemSub_C {
-    
-} BattleSystemSub_C;
-
 struct BattleSystem {
     u32 *unk0;
     BgConfig *bgConfig;
@@ -557,7 +557,7 @@ struct BattleSystem {
     u32 *unk1CC;
     UnkBattleSystemSub1D0 unk1D0[4];
     UnkBattleSystemSub220 unk220;
-    u32 *unk22C;
+    GAME_STATS *gameStats;
     u8 *unk230;
     u16 *unk234;
     u8 sendBuffer[0x1000];
@@ -589,14 +589,14 @@ struct BattleSystem {
     u16 unk2422;
     int unk2424;
     int unk2428;
-    int unk242C;
+    int weather;
     int unk2430;
     u32 unk2434;
     int unk2438;
     int unk243C;
-    u8 unk2440;
-    u8 unk2441;
-    u32 unk2442;
+    int unk2440;
+    u8 unk2442;
+    u8 unk2445;
     u32 unk2444;
     u32 unk2448;
     u16 unk244C[4];
diff --git a/include/battle/battle_hp_bar.h b/include/battle/battle_hp_bar.h
new file mode 100644
index 000000000..4a7d2a27f
--- /dev/null
+++ b/include/battle/battle_hp_bar.h
@@ -0,0 +1,10 @@
+#ifndef POKEHEARTGOLD_BATTLE_HP_BAR_H
+#define POKEHEARTGOLD_BATTLE_HP_BAR_H
+
+#include "battle.h"
+
+void BattleHpBar_LoadResources(BattleHpBar *hpBar);
+void ov12_02264F28(BattleHpBar *hpBar, BOOL a1);
+u8 ov12_02265B64(u8 a0, u32 battleType);
+
+#endif
diff --git a/include/battle_system.h b/include/battle_system.h
index 10920d497..a0e5f6292 100644
--- a/include/battle_system.h
+++ b/include/battle_system.h
@@ -79,6 +79,33 @@ void BattleSystem_TryChangeForm(BattleSystem *bsys);
 void ov12_0223B854(BattleSystem *bsys, int battlerId, int selectedMonIndex);
 void ov12_0223B870();
 void BattleSystem_SetBackground(BattleSystem *bsys);
+u8 *ov12_0223BAD0(BattleSystem *bsys);
+u16 *ov12_0223BAD8(BattleSystem *bsys);
+u16 *ov12_0223BAE0(BattleSystem *bsys);
+u16 *ov12_0223BAEC(BattleSystem *bsys);
+int BattleSystem_GetWeather(BattleSystem *bsys);
+u8 ov12_0223BB04(BattleSystem *bsys);
+void ov12_0223BB10(BattleSystem *bsys, u8 a1);
+int ov12_0223BB1C(BattleSystem *bsys);
+void BattleSystem_GameStatIncrement(BattleSystem *bsys, int id);
+void ov12_0223BB44(BattleSystem *bsys);
+void ov12_0223BB64(BattleSystem *bsys, int a1);
+void ov12_0223BB6C(BattleSystem *bsys, u8 a1);
+void *ov12_0223BB78(BattleSystem *bsys);
+void ov12_0223BB80(BattleSystem *bsys, void *a1);
+UnkBattleSystemSub1D0 *ov12_0223BB88(BattleSystem *bsys, int index);
+u8 *ov12_0223BB94(UnkBattleSystemSub1D0 *ptr, int index);
+void ov12_0223BBA8(UnkBattleSystemSub1D0 *ptr, int index, int a2);
+void ov12_0223BBC0(UnkBattleSystemSub1D0 *ptr, int index, int a2);
+void ov12_0223BBD8(UnkBattleSystemSub1D0 *ptr, int index, int a2);
+void ov12_0223BBF0(BattleSystem *bsys, u8 a1);
+void ov12_0223BBFC(BattleSystem *bsys, u8 *a1);
+void ov12_0223BC08(BattleSystem *bsys, u8 *a1);
+void ov12_0223BC14(BattleSystem *bsys, u8 a1);
+void ov12_0223BC20(BattleSystem *bsys, u8 a1);
+void ov12_0223BC2C(BattleSystem *bsys, u8 a1);
+BattleHpBar *BattleSystem_GetHpBar(BattleSystem *bsys, int battlerId);
+void BattleSystem_HpBar_Init(BattleSystem *bsys);
 
 //These functions haven't been decompiled
 int BattleSystem_Random(BattleSystem *bsys);
@@ -90,12 +117,12 @@ BOOL ov12_0223C080(BattleSystem *bsys);
 void ov12_0223BFFC(BattleSystem *bsys, u32 a1);
 u32 BattleSystem_GetWinLoseFlags(BattleSystem *bsys);
 void ov12_0223C0C4(BattleSystem *bsys);
-int BattleSystem_GetWeather(BattleSystem *bsys);
 BOOL ov12_0223BFEC(BattleSystem *bsys);
-void ov12_0223BB64(BattleSystem *bsys, int a1);
 void ov12_02237ED0(BattleSystem *bsys, int a1);
 void ov12_022642F0(BattleSystem *bsys);
 BOOL ov12_022581BC(BattleSystem *bsys, BATTLECONTEXT *ctx);
 void ov12_02263A1C(BattleSystem *bsys, BATTLECONTEXT *ctx, int battlerId);
 void ov12_02266008(UnkBattleSystemSub17C *a0);
+BattleHpBar *OpponentData_GetHpBar(OpponentData *opponentData);
+
 #endif
diff --git a/main.lsf b/main.lsf
index 8d244552b..e75a0d880 100644
--- a/main.lsf
+++ b/main.lsf
@@ -575,7 +575,7 @@ Overlay OVY_12
     Object asm/overlay_12_battle_controller_opponent.o
     Object asm/overlay_12_02261FD4.o
     Object asm/overlay_12_battle_controller.o
-    Object asm/overlay_12_02264824.o
+    Object asm/overlay_12_hp_bar.o
     Object asm/overlay_12_02265E28.o
     Object src/battle/battle_input.o
     Object asm/overlay_12_02266024.o
diff --git a/src/battle/battle_system.c b/src/battle/battle_system.c
index b0eb890d2..2cd662a1f 100644
--- a/src/battle/battle_system.c
+++ b/src/battle/battle_system.c
@@ -1,4 +1,5 @@
 #include "global.h"
+#include "battle/battle_hp_bar.h"
 #include "battle_controller_opponent.h"
 #include "battle_system.h"
 #include "party.h"
@@ -881,3 +882,130 @@ void BattleSystem_SetBackground(BattleSystem *bsys) {
     ov12_02266008(&bsys->unk17C[0]);
     ov12_02266008(&bsys->unk17C[1]);
 }
+
+u8 *ov12_0223BAD0(BattleSystem *bsys) {
+    return bsys->unk230;
+}
+
+u16 *ov12_0223BAD8(BattleSystem *bsys) {
+    return bsys->unk234;
+}
+
+u16 *ov12_0223BAE0(BattleSystem *bsys) {
+    return &bsys->unk2238[0];
+}
+
+u16 *ov12_0223BAEC(BattleSystem *bsys) {
+    return &bsys->unk2318[0];
+}
+
+int BattleSystem_GetWeather(BattleSystem *bsys) {
+    return bsys->weather;
+}
+
+u8 ov12_0223BB04(BattleSystem *bsys) {
+    return bsys->unk2421;
+}
+
+void ov12_0223BB10(BattleSystem *bsys, u8 a1) {
+    bsys->unk2421 = a1;
+}
+
+int ov12_0223BB1C(BattleSystem *bsys) {
+    return bsys->unk2430;
+}
+
+void BattleSystem_GameStatIncrement(BattleSystem *bsys, int id) {
+    if (bsys->battleSpecial & BATTLE_SPECIAL_RECORDED) {
+        return;
+    }
+    GameStats_Inc(bsys->gameStats, id);
+}
+
+void ov12_0223BB44(BattleSystem *bsys) {
+    if (bsys->battleSpecial & BATTLE_SPECIAL_RECORDED) {
+        return;
+    }
+    GameStats_AddSpecial(bsys->gameStats, 21);
+}
+
+void ov12_0223BB64(BattleSystem *bsys, int a1) {
+    bsys->unk2440 = a1;
+}
+
+void ov12_0223BB6C(BattleSystem *bsys, u8 a1) {
+    bsys->unk2442 = a1;
+}
+
+void *ov12_0223BB78(BattleSystem *bsys) {
+    return bsys->unk1BC;
+}
+
+void ov12_0223BB80(BattleSystem *bsys, void *a1) {
+    bsys->unk1BC = a1;
+}
+
+UnkBattleSystemSub1D0 *ov12_0223BB88(BattleSystem *bsys, int index) {
+    return &bsys->unk1D0[index];
+}
+
+u8 *ov12_0223BB94(UnkBattleSystemSub1D0 *ptr, int index) {
+    GF_ASSERT(index < 4);
+    return ptr[index].unk0;
+}
+
+void ov12_0223BBA8(UnkBattleSystemSub1D0 *ptr, int index, int a2) {
+    GF_ASSERT(index < 4);
+    ptr[index].unk4 = a2;
+}
+
+void ov12_0223BBC0(UnkBattleSystemSub1D0 *ptr, int index, int a2) {
+    GF_ASSERT(index < 4);
+    ptr[index].unk8 = a2;
+}
+
+void ov12_0223BBD8(UnkBattleSystemSub1D0 *ptr, int index, int a2) {
+    GF_ASSERT(index < 4);
+    ptr[index].unkC = a2;
+}
+
+void ov12_0223BBF0(BattleSystem *bsys, u8 a1) {
+    bsys->unk23FD = a1;
+}
+
+void ov12_0223BBFC(BattleSystem *bsys, u8 *a1) {
+    bsys->unk23F4 = a1;
+}
+
+void ov12_0223BC08(BattleSystem *bsys, u8 *a1) {
+    bsys->unk23F8 = a1;
+}
+
+void ov12_0223BC14(BattleSystem *bsys, u8 a1) {
+    *bsys->unk23F4 = a1;
+}
+
+void ov12_0223BC20(BattleSystem *bsys, u8 a1) {
+    *bsys->unk23F8 = a1;
+}
+
+void ov12_0223BC2C(BattleSystem *bsys, u8 a1) {
+    bsys->unk23FE = a1;
+}
+
+BattleHpBar *BattleSystem_GetHpBar(BattleSystem *bsys, int battlerId) {
+    return OpponentData_GetHpBar(bsys->opponentData[battlerId]);
+}
+
+void BattleSystem_HpBar_Init(BattleSystem *bsys) {
+    int i;
+    BattleHpBar *hpBar;
+    
+    for (i = 0; i < bsys->maxBattlers; i++) {
+        hpBar = OpponentData_GetHpBar(bsys->opponentData[i]);
+        hpBar->bsys = bsys;
+        hpBar->type = ov12_02265B64(ov12_02261258(bsys->opponentData[i]), BattleSystem_GetBattleType(bsys));
+        BattleHpBar_LoadResources(hpBar);
+        ov12_02264F28(hpBar, FALSE);
+    }
+}