Bitterblade Warrior is a common Creature — Jackal Warrior card from Amonkhet (AKH), collector number 157. Current market price: $0.13 (foil $0.24), TCGplayer market prices via Scryfall.
You may exert this creature as it attacks. When you do, it gets +1/+0 and gains deathtouch until end of turn. (An exerted creature won't untap during your next untap step.)