Mizuki

Mizuki's shoulder-length hair is white with a faint blue tint, set above green eyes. Before his defection he wears the usual Leaf uniform, flak jacket included, with his headband tied bandanna-style. Imprisonment changes him: in the anime he dons a grey prison tunic and goes barefoot, and long training leaves him so heavily muscled that Naruto fails to recognize him. After breaking out he switches to an open black vest, tight black pants, and a brown belt with a silver buckle. The potion brewed from his cursed seal gives him tiger stripes and a feral cast, and when its power fails he withers into a frail, brown-skinned old man, an effect Tsunade later reverses.

Behind an outwardly polite and gentle manner, praised as sweet by his former fiancee Tsubaki, Mizuki cares for no one but himself. He prizes being unbound by morals or teamwork and will sacrifice anything to reach his goals, a drive rooted in a gnawing inferiority complex; he cannot bear to be looked down upon, yet delights in looking down on others. His resentment of Iruka, whose warmth won him the attention Mizuki craved, festers into a manipulated friendship kept alive only to keep Iruka miserable. Cruelty comes easily to him, whether savoring a grieving Iruka's misery as a child or gleefully smothering an injured comrade he deemed a burden. He scorns the Will of Fire as irritating nonsense, harbors a special loathing for Naruto that reduces the boy to the Nine-Tailed Demon Fox in his eyes, and even names ramen, Naruto's favorite, as the food he hates most.

In the anime, Mizuki and Iruka are childhood friends, but jealousy sours the bond once Iruka begins drawing everyone's favor. On a document-recovery mission, Mizuki suffocates a wounded teammate rather than let the injury slow them, then lies about the cause of death. Orochimaru witnesses the killing, praises his ruthlessness, and hands him a prototype cursed seal. When the resulting suspicion nearly costs Mizuki an Academy teaching post, his contempt for Konoha hardens, and he resolves to seize power by any means as Orochimaru's secret follower. His scheme centers on the Scroll of Seals: he cons Naruto into stealing it, planning to kill the boy as a scapegoat and slip away, but Iruka's defense of Naruto inspires the youngster to fell Mizuki with a swarm of shadow clones. In the manga little of his skill is shown beyond wielding oversized shuriken, though he boasts that the scroll could grant him limitless power. The anime paints him as a cunning, self-taught fighter who chains improvised techniques together, using Earth Release to strike from below and pairing illusions with puppetry to finish foes from a distance. Jailed and given the number 99, he bulks up, stages a riot, and escapes to brew Orochimaru's power-boosting potion, besting Iruka again with his new arsenal before consuming the formula. It swells his strength and marks him with stripes, and a tiger extract turns him into a hulking tiger-beast, yet Naruto downs him with the Rasengan. The flawed seal then withers Mizuki into a decrepit old man; Tsunade halts his collapse and restores his looks but cannot give back his ninja powers, and he is returned to prison stripped of them.