Seraph

A combat-damage steal mechanic that few designs have revisited, and the reason is written into the body itself. The trigger keys off any damage this creature dealt to a creature that turn: connect with a blocker or an attacker, and if that creature dies before end of turn (from this damage, from a later trade, from a removal spell, from anything), it returns under your control. You are not draining the board, you are converting kills into permanents one at a time, and only the ones this Angel had a hand in. The delay until the next end step matters: the stolen card does not return until after combat resolves, so it cannot block or attack the turn it is claimed, and the controller has a full window to respond before the gain lands. The leash clause closes the loop in the other direction: lose control of the Angel and every creature it pulled in is sacrificed, so the theft survives only as long as the thief does. That tether is what keeps the engine from snowballing into a runaway advantage; the value is real but conditional, contingent on protecting a 4/4 flier that wants to be in the red zone. It is the rare angel whose reward scales with how willingly it trades blows rather than how safely it sits back, a design that pays off precisely because it courts combat instead of avoiding it.