Martyr of Dusk

Kill it and it thanks you. A 2/1 that trades willingly in combat and then hands back a lifelinking 1/1 does the same converting-a-death-into-value work white token-makers have always done, refunding half of itself the moment an opponent spends a block or an answer on it. The lifelink on the token is where the real work happens, not decoration: it turns each death into a trickle of life gain for grindy decks, and it gives the leftover body a reason to keep standing on defense. Feed the front half to a sacrifice engine and the payload staggers nicely: a death trigger now, a lifelinking blocker later, and the token itself waiting as a second thing to sacrifice. That two-stage shape (a body eager to die, a body worth keeping) rewards being killed twice, and the creature you actually want is the one that arrives second. Built as a common-rarity engine piece for go-wide and life-drain shells, it wants only a steady demand for small white creatures to do its work.