In Garruk's Wake

The asymmetry is the whole pitch, and the price tag is what makes it honest. A board wipe that leaves your own creatures and planeswalkers standing has to cost something, and nine mana is the toll: by the turn you cast this, you are meant to have a board worth protecting and an opponent's that you would rather not lose your own pieces to clear. That places it in the lineage of one-sided sweepers that ask you to earn the exception, the way Plague Wind or a Cleansing Nova built for keeps would, rather than the symmetric Damnation school that resets everyone equally. The planeswalker clause is the quiet upgrade: most black mass-removal of earlier eras stopped at creatures, and a sweeper that also strips an opposing superfriends board does work that a Mutilate or a Crux of Fate cannot. What it buys, then, is not tempo but a clean slate that is only clean for the other side: you keep your engine, your blockers, your closer, and walk into a turn where nothing across the table is left to interact. The catch is that nine mana arrives late enough that the game is often already decided one way or the other, which is why this lives in the decks that ramp hard or grind long and want a button that ends the stalemate in their favor.