Cultist of the Absolute is a rare Legendary Enchantment — Background card from Commander Legends: Battle for Baldur's Gate (CLB), collector number 123. Current market price: $0.41 (foil $1.45), TCGplayer market prices via Scryfall.
Commander creatures you own get +3/+3 and have flying, deathtouch, "Ward—Pay 3 life," and "At the beginning of your upkeep, sacrifice a creature."
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