Zangetsu (Zanpakutō spirit)

This spirit is a near mirror of Ichigo, only bleached and reversed. His skin, hair, and robes run stark white, his shihakushō inverted until it resembles an Arrancar's garb belted in black, while his mouth holds black teeth over a blue tongue and his eyes stare with black pupils on white irises ringed by black sclera, his nails darkened to match.

In his Hollowfied and Bankai states he echoes Ichigo's own monstrous forms, sporting a color-flipped horned mask, waist-length white hair, and pale claws.

Cackling and wearing a deranged grin, this Zangetsu is contemptuous and cruel, endlessly taunting Ichigo as too feeble to fight and dropping mocking false apologies. He revels in slaughter, tearing into enemies with berserk ferocity and no trace of mercy, and he scorns Ichigo's habit of thinking his way through a battle.

He is convinced that only a raw, primal hunger for destruction, a genuine killer instinct, makes a true ruler. Casting Ichigo as the king of their shared inner world and himself as the horse, he swears he will unseat any king weaker than he is and claim the crown for his own.

He is the product of two inheritances fused together: the Hollow called White, passed down from Ichigo's mother, merged with the Shinigami power that came from his father. His presence first surfaces as a mask that reappears over Ichigo's face during desperate fights, once even stopping Zabimaru near the heart.

During the near-fatal duel with Kenpachi Zaraki, the Quincy manifestation drags Ichigo into the inner world and hurls the sword to this spirit, who forces Ichigo to prove himself worthy of wielding him. He seizes control of Ichigo's body outright against Byakuya Kuchiki, carving the captain open and firing a black Getsuga Tenshō while boasting that he has no name. Only in the Quincy war is his real nature settled, when Ōetsu Nimaiya reforges him, alongside the Quincy spirit, into a proper Asauchi and Ichigo at last claims him as his genuine Zanpakutō.