Liliana's Devotee is a uncommon Creature — Human Warlock card from Core Set 2021 (M21), collector number 298. Current market price: $0.13 (foil $0.32), TCGplayer market prices via Scryfall.
Zombies you control get +1/+0. At the beginning of your end step, if a creature died this turn, you may pay {1}{B}. If you do, create a 2/2 black Zombie creature token.