Shadowheart, Dark Justiciar

The exchange rate on most black sacrifice outlets is fixed: a body for one card, sometimes two, and the fodder is small and disposable by design. This inverts that math by tying the payout to the sacrificed creature's power, which pulls the card against its own color's instincts. Feed it black's usual expendable chaff and you draw one; feed it a fat token or a pumped attacker and you refuel an entire hand for two mana and a tap. The ability reads less like an aristocrats grinder and more like a permission slip to overcommit, and it steers the deck toward cheap large bodies or on-demand pump rather than the go-wide swarms it superficially resembles. The 3/4 body for four is no bargain, and the engine only comes online once you can afford both the cast and its recurring tax on each activation. The structural piece is Choose a Background: pairing a raw card-draw outlet with a chosen thematic anchor splits the deck's identity across two command-zone slots, so the draw is available from the command zone every time. That access is the point. A commander that converts creature power into cards on demand stops functioning as a single spell and starts functioning as an economy, one that rewards building around threats worth throwing away rather than threats worth keeping.