Sultai Emissary is a common Creature — Zombie Warrior card from Fate Reforged (FRF), collector number 85. Current market price: $0.21 (foil $0.35), TCGplayer market prices via Scryfall.
When this creature dies, manifest the top card of your library. (Put that card onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)