Eliminate the Competition
The math punishes you for casting it. Five mana buys nothing on its own; the spell only kills as many creatures as you can feed it, and every body you sacrifice to the additional cost is a creature you owned a moment ago. That makes this a one-sided board wipe in theory and a wash in practice, the kind of symmetrical-looking effect that wants a board state already lopsided in your favor: a wide swarm of expendable tokens, a sacrifice payoff that turns the entry fee into value, or an engine that spins out fodder faster than it commits real threats. The asymmetry has to be supplied from elsewhere, because the card refuses to provide it itself. Most mass removal in black taxes you in life or restricts what dies; this one taxes you in creatures, which is a stranger and harder currency to part with. The destruction itself is the clean half of the effect, but it is ordinary destruction: a creature with regeneration or indestructible shrugs it off the way it shrugs off any "destroy" clause, so the spell offers no escape hatch around those. The real design problem lives in the additional cost, and that cost is steep enough that the whole card lives or dies on whether you have a board that wants to liquidate itself.


