Witch-king, Sky Scourge

Rakdos impulse-draw has usually been transactional: hit a creature or a face, exile a couple off the top, spend them before the turn ends. This scales the whole engine to the board instead of the trigger. The exile count keys off total attacking Wraith power, so a wide or wide-and-fat wraith board doesn't dig deeper by casting more spells; it digs deeper by committing more bodies to the red zone, and every point of power in the swing turns into another card you can play that turn. That folds card advantage and combat into a single decision: the more you're willing to expose to blocks and removal, the more fuel you draw to rebuild. Undying is the counterweight that makes the aggression cheap to underwrite. A 5/5 flier that returns as a 6/6 the first time it dies means the attack that fills your hand is also hard to punish; you commit the Witch-king to the swing, trade or die, and it comes back bigger while your other Wraiths keep the impulse count high. The two halves reinforce each other: the recursion invites you to attack into unfavorable math, and attacking into that math is exactly what powers the refill. It is a lord-slot payoff built for a tribe that wants to go wide, stay wide, and turn the swing step itself into the draw step.