Grim Servant is a uncommon Creature — Zombie Warlock card from Modern Horizons 3 (MH3), collector number 409. Current market price: $0.32 (foil $0.38), TCGplayer market prices via Scryfall.
Menace When this creature enters, search your library for a card with mana value less than or equal to your devotion to black, reveal it, put it into your hand, then shuffle. You lose 3 life. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)