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.

Coven — At the beginning of combat on your turn, put a +1/+1 counter on up to one target creature you control. Then if you control three or more creatures with different powers, draw a card.