Ob Nixilis Resilient

Flying, Lifelink, Nosferatu (Each permanent you sacrifice while casting this card pays for {1}.)
{t}Exile 2 cards from your graveyard: Destroy target nonartifact, nonblack creature. It can't be regenerated. If a green creature is destroyed this way, its controller discards a card.

The Gatewatch is just another enemy to swear revenge upon.