diff --git a/asm/non_matching/common/sub_0801E99C.inc b/asm/non_matching/common/sub_0801E99C.inc
deleted file mode 100644
index 7bbda3c9..00000000
--- a/asm/non_matching/common/sub_0801E99C.inc
+++ /dev/null
@@ -1,112 +0,0 @@
-    .syntax unified
-	push {r4, r5, r6, r7, lr}
-	mov r7, r8
-	push {r7}
-	bl sub_08002632
-	mov r8, r0
-	ldr r1, _0801E9E4 @ =gUnk_08001DCC
-	lsls r0, r0, #2
-	adds r0, r0, r1
-	ldr r7, [r0]
-	movs r0, #0x67
-	bl GetInventoryValue
-	cmp r0, #0
-	beq _0801EA56
-	ldr r1, _0801E9E8 @ =gSave
-	ldrb r0, [r7]
-	ldrb r2, [r1, #8]
-	cmp r0, r2
-	bhi _0801EA56
-	ldr r2, _0801E9EC @ =0x000001C1
-	adds r0, r1, r2
-	add r0, r8
-	ldrb r5, [r0]
-	subs r2, #0x80
-	adds r0, r1, r2
-	add r0, r8
-	ldrb r6, [r0]
-	adds r4, r6, r7
-_0801E9D6:
-	cmp r5, #0xf1
-	beq _0801E9F6
-	cmp r5, #0xf1
-	bhi _0801E9F0
-	cmp r5, #0
-	beq _0801E9F6
-	b _0801EA10
-	.align 2, 0
-_0801E9E4: .4byte gUnk_08001DCC
-_0801E9E8: .4byte gSave
-_0801E9EC: .4byte 0x000001C1
-_0801E9F0:
-	cmp r5, #0xf2
-	beq _0801EA0A
-	b _0801EA10
-_0801E9F6:
-	ldrb r5, [r4, #5]
-	cmp r5, #0
-	beq _0801EA10
-	cmp r5, #0xff
-	beq _0801EA14
-	adds r0, r5, #0
-	bl CheckKinstoneFused
-	cmp r0, #0
-	beq _0801EA10
-_0801EA0A:
-	adds r4, #1
-	adds r6, #1
-	ldrb r5, [r4, #5]
-_0801EA10:
-	cmp r5, #0xff
-	bne _0801EA1C
-_0801EA14:
-	adds r0, r7, #0
-	bl sub_0801EA74
-	adds r5, r0, #0
-_0801EA1C:
-	cmp r5, #0
-	beq _0801EA32
-	cmp r5, #0xf2
-	beq _0801E9D6
-	adds r0, r5, #0
-	bl CheckKinstoneFused
-	cmp r0, #0
-	beq _0801EA34
-	movs r5, #0xf1
-	b _0801E9D6
-_0801EA32:
-	movs r5, #0xf3
-_0801EA34:
-	ldr r1, _0801EA5C @ =gSave
-	ldr r2, _0801EA60 @ =0x000001C1
-	adds r0, r1, r2
-	add r0, r8
-	strb r5, [r0]
-	subs r2, #0x80
-	adds r0, r1, r2
-	add r0, r8
-	strb r6, [r0]
-	bl Random
-	ldrb r4, [r7, #1]
-	movs r1, #0x64
-	bl __modsi3
-	cmp r4, r0
-	bhi _0801EA64
-_0801EA56:
-	movs r0, #0
-	b _0801EA6E
-	.align 2, 0
-_0801EA5C: .4byte gSave
-_0801EA60: .4byte 0x000001C1
-_0801EA64:
-	subs r0, r5, #1
-	cmp r0, #0x63
-	bls _0801EA6C
-	movs r5, #0
-_0801EA6C:
-	adds r0, r5, #0
-_0801EA6E:
-	pop {r3}
-	mov r8, r3
-	pop {r4, r5, r6, r7, pc}
-    .syntax divided
diff --git a/include/common.h b/include/common.h
index 5d68679b..4fcf2be6 100644
--- a/include/common.h
+++ b/include/common.h
@@ -124,6 +124,7 @@ void sub_0801DFB4(struct Entity_*, u32, u32, u32);
 u32 sub_0801E00C(void);
 bool32 sub_0801E810(u32);
 u32 sub_0801DB94(void);
+u32 sub_0801EA74(u8*);
 
 typedef struct {
     u8 unk_0;
diff --git a/src/common.c b/src/common.c
index 0ad58ee5..909dd944 100644
--- a/src/common.c
+++ b/src/common.c
@@ -5,6 +5,7 @@
 #include "functions.h"
 #include "game.h"
 #include "global.h"
+#include "item.h"
 #include "kinstone.h"
 #include "main.h"
 #include "message.h"
@@ -966,7 +967,64 @@ void sub_0801E8D4(void) {
     }
 }
 
-ASM_FUNC("asm/non_matching/common/sub_0801E99C.inc", u32 sub_0801E99C(u32 a1));
+extern u8* gUnk_08001DCC[];
+
+u32 sub_0801E99C(Entity* entity) {
+    u8* fuserData;
+    u32 fuserId;
+    u32 offeredFusion;
+    u32 fuserProgress;
+    u8* fuserFusionData;
+    s32 randomMood;
+    u32 fuserStability;
+    fuserId = sub_08002632(entity);
+    fuserData = gUnk_08001DCC[fuserId];
+    if (GetInventoryValue(ITEM_KINSTONE_BAG) == 0 || fuserData[0] > gSave.global_progress) {
+        return 0;
+    }
+    offeredFusion = gSave.unk1C1[fuserId];
+    fuserProgress = gSave.unk141[fuserId];
+    fuserFusionData = (u8*)(fuserProgress + (u32)fuserData);
+    while (TRUE) { // loop through fusions for this fuser
+        switch (offeredFusion) {
+            case 0xF1: // offered fusion completed with someone else
+            case 0x00: // no fusion offered yet
+                offeredFusion = fuserFusionData[5];
+                if (offeredFusion == 0x00 || offeredFusion == 0xFF || CheckKinstoneFused(offeredFusion) == 0) {
+                    break;
+                }
+            case 0xF2: // previous fusion completed
+                fuserFusionData++;
+                fuserProgress++;
+                offeredFusion = fuserFusionData[5];
+        }
+        if (offeredFusion == 0xFF) { // random shared fusion
+            offeredFusion = sub_0801EA74(fuserData);
+        }
+        if (offeredFusion == 0x00) { // end of fusion list
+            offeredFusion = 0xF3;    // mark this fuser as done
+            break;
+        }
+        if (offeredFusion == 0xF2) { // previous fusion completed
+            continue;
+        }
+        if (CheckKinstoneFused(offeredFusion) == 0) {
+            break;
+        }
+        offeredFusion = 0xF1; // already completed, try next fusion in the list
+    }
+    gSave.unk1C1[fuserId] = offeredFusion;
+    gSave.unk141[fuserId] = fuserProgress;
+    randomMood = Random();
+    fuserStability = fuserData[1];
+    if (fuserStability <= randomMood % 100) {
+        return 0; // fickleness
+    }
+    if (offeredFusion - 1 > 99) {
+        offeredFusion = 0;
+    }
+    return offeredFusion;
+}
 
 const struct_080C9C6C gUnk_080C9C6C[] = {
     { 1, 2, 2 }, { 3, 3, 3 }, { 4, 3, 0 }, { 3, 5, 5 }, { 3, 2, 2 }, { 5, 7, 7 }, { 5, 5, 5 }, { 1, 3, 3 },
@@ -1135,7 +1193,7 @@ const u8 gUnk_080CA11C[] = {
 };
 
 // Get a random kinstone
-u32 sub_0801EA74(void) {
+u32 sub_0801EA74(u8* fuserData) {
     s32 r = (s32)Random() % 18;
     u32 i;
     for (i = 0; i < 18; ++i) {