Krav, the Unredeemed is a rare Legendary Creature — Demon card from Battlebond (BBD), collector number 4. Current market price: $2.65 (foil $6.90), TCGplayer market prices via Scryfall.
Partner with Regna, the Redeemer (When this creature enters, target player may put Regna into their hand from their library, then shuffle.) {B}, Sacrifice X creatures: Target player draws X cards and gains X life. Put X +1/+1 counters on Krav.