Knight of the Black Blood

Deathtouch, lifelink, menace
At the beginning of your upkeep, put a -1/-1 counter on Knight of the Black blood for each -1/-1 counter on it, then put a -1/-1 counter on it.
Whenever Knight of the Blackbloods deals combat damage to an opponent, remove all -1/-1 counters from it.
With power comes a price of blood.