Kurosaki Ichigo's Zanpakuto, manifesting as a tall man with facial hair and long, black hair, and wears sunglasses with a black coat that covers most of his body.
In Bankai form, he becomes a younger version of himself, with shorter hair, no facial hair, and no sunglasses.
During the Thousand-Year Blood War, it is revealed that the person formally identified as Zangetsu is in fact a manifestation of Ichigo’s Quincy powers, being a portion of Yhwach's soul.