Finishing Blow

Five mana for unconditional removal that hits creatures and planeswalkers alike is the deliberately overcosted end of black's kill-spell spectrum, and that price is the whole design. Black has always been able to destroy anything it wants; the tension in every generation of its removal is how cheaply and how flexibly. Hero's Downfall did this same "creature or planeswalker" job at three mana and defined a control staple, which is exactly why this version pays for its total lack of drawback text with a heavy rate instead. There is no life payment, no exile clause, no restriction on the target's toughness. It is the plainest possible version of the effect, sold at a cost that keeps it out of the way of the format's more efficient answers. What that buys is reliability rather than reach: a spell that can never whiff on a target, priced so it never crowds out the tighter removal a serious deck actually wants. The instant speed lets it hold up in combat or wait until the caster has nothing better to do, but five mana is enough that the tempo rarely justifies the payoff. It is a floor, not a ceiling: the version of black removal that answers "can I kill it?" with a flat yes, and leaves the question of whether you can afford to for the rest of the spectrum to solve.