Assemble the Legion is a rare Enchantment card from Gatecrash (GTC), collector number 142. Current market price: $0.31 (foil $2.16), TCGplayer market prices via Scryfall.
At the beginning of your upkeep, put a muster counter on this enchantment. Then create a 1/1 red and white Soldier creature token with haste for each muster counter on this enchantment.