Karlov of the Ghost Council is a mythic Legendary Creature — Spirit Advisor card from Ravnica Remastered (RVR), collector number 193. Current market price: $15.26 (foil $15.94), TCGplayer market prices via Scryfall.
Whenever you gain life, put two +1/+1 counters on Karlov. {W}{B}, Remove six +1/+1 counters from Karlov: Exile target creature.