Haku

Haku is kind, polite, perceptive, and reluctant to inflict unnecessary suffering. This temperament sharply contrasts with the violent environment in which he grows up and with Zabuza's reputation as the Demon of the Hidden Mist.

He believes strength comes from protecting someone precious. After losing his family and wandering alone, being needed by Zabuza gives Haku a reason to live, and he commits himself completely to helping Zabuza achieve his ambitions.

That devotion is so extreme that Haku accepts being described as a tool. He does not consider the term degrading because usefulness to Zabuza has become inseparable from his own sense of identity.

Haku nevertheless retains compassion toward enemies. He avoids killing when he can achieve his objective through incapacitation and recognizes Naruto's own desire to become stronger for the sake of others.

Haku possesses Ice Release, a hereditary kekkei genkai that combines Water and Wind Release. He can create and manipulate ice even under conditions where ordinary freezing would be difficult.

His signature technique is Demonic Mirroring Ice Crystals, which surrounds an opponent with ice mirrors. Haku enters the mirrors and moves between them at tremendous speed, attacking from numerous directions with senbon.

His speed while using the mirrors is so great that early-series Sasuke struggles to follow him even after beginning to use the Sharingan more effectively.

Haku is an expert with senbon, throwing the thin needles with exceptional anatomical precision. He can strike points that render a target apparently dead without necessarily causing permanent injury.

He also demonstrates medical knowledge, stealth, and one-handed hand seals, an uncommon level of technical control.

Haku first appears disguised as a Kirigakure hunter-nin after Kakashi defeats Zabuza. He seemingly kills Zabuza with senbon and removes the body, but the attack actually places Zabuza into a temporary death-like state so Haku can rescue him.

Naruto later meets Haku in the forest without recognizing him as an enemy. Their conversation establishes Haku's belief that people become truly strong when they have someone precious to protect.

During the second battle on the bridge, Haku traps Naruto and Sasuke Uchiha inside Demonic Mirroring Ice Crystals.

Although Haku has opportunities to strike lethally, his reluctance to kill affects the battle. Sasuke gradually begins perceiving his movements with the Sharingan, while Naruto's anger draws upon the Nine-Tails' chakra.

When Kakashi prepares to kill Zabuza with Lightning Blade, Haku abandons his battle with Naruto and places himself in front of the attack, sacrificing himself to save Zabuza.

Naruto later condemns Zabuza for treating Haku as a tool despite Haku's complete devotion. His words finally cause Zabuza to acknowledge his feelings for Haku.

Haku and Zabuza are later resurrected through Edo Tensei during the Fourth Shinobi World War and forced to fight Kakashi's division before being sealed.

Zabuza Momochi gives Haku purpose after finding him alone and homeless. Haku dedicates his life to Zabuza Momochi and accepts being his weapon, while Zabuza ultimately admits through his grief that Haku meant far more to him than a disposable tool.

Naruto Uzumaki meets Haku without initially knowing his identity. Haku's words about becoming strong to protect someone precious leave a lasting impression on Naruto Uzumaki.

Sasuke Uchiha fights Haku inside the ice mirrors. Sasuke Uchiha's developing Sharingan gradually allows him to follow Haku's extraordinary speed.

Haku's Mother possesses the Ice Release kekkei genkai and passes it to Haku. After Haku innocently reveals the same ability, his frightened father kills her.

Haku's Father fears kekkei genkai because of the violence surrounding bloodline users in the Land of Water. He attempts to kill Haku after murdering Haku's mother, but Haku instinctively kills him and the accompanying villagers with Ice Release.

Kakashi Hatake becomes the immediate threat that prompts Haku's final act of protecting Zabuza from Lightning Blade.