Nether Traitor

Recursion priced per-trigger rather than per-turn, which is the whole engine. The graveyard-to-battlefield clause keys on any other creature your side loses, so the cost is paid in mana but the fuel is attrition: every time a body dies, you get the option to bring this one back for a single black. In a deck built to sacrifice creatures repeatedly (an aristocrats shell, a token engine, anything with a free outlet), it doubles as a reusable death-trigger and a reusable piece of fodder in the same card, looping as fast as the mana and the deaths come. The evasion is what makes the recursion worth chasing: shadow keeps the body in its own combat lane, untouchable by anything that lacks the keyword, so a 1/1 that comes back over and over reads as an inevitable clock instead of a chump. The two abilities pull against each other and serve the same plan: the evasion keeps it attacking, the recursion keeps it coming back, and haste means each return is immediately relevant. Among the black creatures built to be sacrificed and resurrected on a loop, none asks less to do it: no tribal text, no exile clause, no tap requirement, just a black mana and a creature already on its way to the yard.