Devouring Light

Exile is the premium on this removal, and convoke is what makes the premium affordable. White rarely gets clean exile that strips a creature of regeneration, indestructibility, and death triggers in one step, and when it does, the rate usually reflects that ceiling. The catch is the target line: this only touches attackers and blockers, so it is never a catch-all answer to a threat sitting outside combat. That restriction does not pay for the spell, but it does dictate when you cast it, and the where-and-when is the whole design. The defensive line is the elegant one: declare your blockers, then tap those same blocking creatures (plus anything else you held back) to convoke the exile before combat damage. You absorb the attack on paper, then erase the threat entirely while keeping your own bodies alive, since a tapped blocker that gets the spell paid for is a blocker that never has to trade. On offense the discount is thinner, because the creatures you sent into the red zone are already tapped from being declared as attackers; only the bodies you kept home or anything with vigilance can chip in. The card lives in that gap: it is built to convert a defensive board into an instant-speed exile and a tempo swing, not to clear the path for an alpha strike. With an empty battlefield it does not vanish, it just resolves at its baseline as a three-mana instant exile, a fine fallback and a much better deal whenever the board is wide enough to pay for it cheaply.