Zangetsu is the manifested spirit of Ichigo Kurosaki’s Zanpakutō as well as his inner Hollow. He has been variously called Hollow Ichigo , more properly called The Hollow within Ichigo, Ichigo no naimen no Horō) or White Ichigo 

Zangetsu is the result of the fusion between the Hollow White that Ichigo inherited from his mother and the Shinigami powers he inherited from his father. He has stated himself to represent Ichigo’s purest instincts.

Zangetsu appears to be virtually identical to Ichigo, except inverted in color. He is a fairly tall and lean-built being possessing white skin, a blue tongue, black nails and white hair. His eyes consist of black pupils, white irises, and black sclera. While Ichigo wears a standard black Shinigami shihakushō, his Zanpakutō spirit wears a white shihakushō with a black cloth belt. When he is later pulled out of Ichigo by the manifestation of Ichigo’s Quincy powers, he wears a mask greatly resembling Ichigo’s Hollowfied form from his battle against Ulquiorra Cifer, and has white, waist-length hair along with a white version of Ichigo’s shihakushō in Bankai form.