Frodo, Sauron's Bane

Instant-death triggers almost never live in white, and the design smuggles one in by making Frodo grow into it rather than start with it. He begins as a fragile 1/2 Citizen and levels through the type line itself: two hybrid mana turn him into a Halfling Scout with lifelink, then three black remake him as a Halfling Rogue whose combat damage reads as a hard kill. The condition is where the real work happens. The Rogue only makes an opponent lose if the Ring has tempted you four or more times; otherwise the same hit advances the Ring one step further. So the win button is loaded by the exact mechanic the Rogue keeps feeding, folding the Ring-bearer subtheme into a self-contained clock instead of borrowing the kill from somewhere else. The activation costs track the fiction: cheap and harmless at first, then progressively heavier and blacker the further Frodo is pushed toward the version that ends games. Nothing here changes his color; the card stays white throughout, and only the creature types, stats, and abilities shift underneath it. The whole build lives in the gap between that opening body and a you-lose-the-game clause sitting just two activations away, gated behind a black commitment steep enough to make arming it a real cost rather than a formality.