Solemn Recruit is a rare Creature — Dwarf Warrior card from Aether Revolt (AER), collector number 22. Current market price: $0.16 (foil $0.52), TCGplayer market prices via Scryfall.
Double strike Revolt — At the beginning of your end step, if a permanent left the battlefield under your control this turn, put a +1/+1 counter on this creature.