Avenger of the Fallen is a rare Creature — Human Warrior card from Tarkir: Dragonstorm Promos (PTDM), collector number 73p. Current market price: $0.51 (foil $0.60), TCGplayer market prices via Scryfall.
Deathtouch Mobilize X, where X is the number of creature cards in your graveyard. (Whenever this creature attacks, create X tapped and attacking 1/1 red Warrior creature tokens. Sacrifice them at the beginning of the next end step.)