Bathe in Light

Protection from a color is one of Magic's oldest blanket answers, bundling can't-be-blocked, can't-be-targeted, can't-be-damaged, and can't-be-enchanted-or-equipped into a single keyword. Radiance is the wrinkle that takes that personal shield and broadcasts it: name a color, point at one creature, and that creature plus every other creature on the battlefield sharing a color with it gains protection from the color you named. Two independent choices run the show, and keeping them separate is the whole skill. One choice is the protection color (the threat you want everyone to dodge); the other is the target, whose actual color decides which other creatures inherit the grant. The cleanest line aims at a board where your team shares a color the opponent's removal or blockers cannot reach, fogging a single-color swarm while you race or walking a committed attack through a wall of same-colored defenders. The symmetry is the trap: in a mirror where both armies share the target's color, one cast can shield the opponent's creatures too, so the spell rewards reading whose creatures actually overlap before you commit. Naming exactly one color is what stops this from being a catch-all; protection is absolute against that color and inert against the other four. Instant timing lets both decisions wait until the attack step or until a removal spell is on the stack, when the color worth dodging is finally known and the blanket can be aimed where it lands.