Lord of the Void is a mythic Creature — Demon card from Ravnica Remastered (RVR), collector number 327. Current market price: $9.86 (foil $10.58), TCGplayer market prices via Scryfall.
Flying Whenever this creature deals combat damage to a player, exile the top seven cards of that player's library, then put a creature card from among them onto the battlefield under your control.