By enchanting Cinderhaze Wretch with Splinter Twin, you gain the ability to tap the creature to create an exact token copy of itself with haste, which immediately explodes your board with infinite creature tokens and endless ETB triggers. Normally, Splinter Twin tokens have to wait for your next end step to vanish, but because Cinderhaze Wretch features an activated ability that puts a -1/-1 counter on itself to untap, you can perpetually untap and reuse the original creature to multiply your army without needing to tap the copies at all. Meanwhile, Coat of Arms watches the chaos unfold, naturally granting a massive, stacking power and toughness boost to every single creature on the battlefield that shares a creature type as your growing horde.