Whenever another Zombie you control dies, if it didn't have decayed, create a 2/2 black Zombie creature token with decayed. (It can't block. When it attacks, sacrifice it at end of combat.)
At the beginning of your end step, you may sacrifice a Zombie. If you do, draw a card.
Wilhelt is a UB Zombie tribal engine that turns every zombie death into a fresh decayed token, then converts those tokens into cards each end step. You flood the board with zombies, sacrifice them for value and damage, and grind the table out with relentless card advantage before closing with an overrun, drain, or aristocrats combo.
Self-sustaining card draw engine that refuels every turn end
Wide, resilient board that punishes wraths via decayed token replacement
Excellent fodder for sacrifice payoffs and aristocrats drains
Deep, well-supported tribe in two strong colors
Heavy reliance on the commander; without Wilhelt the engine stalls
Decayed tokens can't block, leaving you vulnerable to aggression
Tokens are small and need anthems or sac payoffs to deal real damage
Vulnerable to graveyard hate and token-hate (Cursed Totem, Torpor-style effects)