Oona's Blackguard is a rare Creature — Faerie Rogue card from DCI Promos (DCI), collector number 15. Current market price: — (foil $7.97), TCGplayer market prices via Scryfall.
Flying Each other Rogue creature you control enters with an additional +1/+1 counter on it. Whenever a creature you control with a +1/+1 counter on it deals combat damage to a player, that player discards a card.