The Last Ronin is a mythic Enchantment — Saga card from Teenage Mutant Ninja Turtles (TMT), collector number 154. Current market price: $0.67 (foil $1.95), TCGplayer market prices via Scryfall.
(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.) I — Destroy all creatures. II — Mill four cards. When you do, return target creature card from your graveyard to your hand. III — Whenever a creature you control attacks alone this turn, put three +1/+1 counters on it. It gains trample, lifelink, and indestructible until end of turn.