Testament, Grim Reaper

At the beginning of your end step, create a 1/1 black Crow creature token with flying.

Whenever another Legendary creature you control would die, you may sacrifice a Crow. If you do, return that creature to the battlefield tapped with a stun counter on it.

Whenever one or more creatures an opponent controls become the target of a spell or ability you control, they gain a -1/-1 counter.