Old Man Zangetsu is the spiritual embodiment of Ichigo Kurosaki's Quincy powers and takes the form of Yhwach the Quincy king. He's been impersonating Zangetsu in order to restrain Ichigo's true powers.
Zangetsu looks like a man somewhere in his late thirties. He has long black hair and scruffy looking stubble on his face. Zangetsu wears semi transparent sunglasses and a long black trench coat with a string connecting the shoulder and the lapel.
As far as his personality goes Zangetsu is serene and straight forward. His actions speak for themselves and he speaks only when he he feels it is necessary.
During the battle against Aizen, Ichigo's father tells him that there is an even greater version of his Getsuga Tenshou attack, and to learn this he must enter the world of his zanpakuto again. Once doing so Ichigo meets up with Old Man Zangetsu again, only this time he has completely changed his appearance. It is revealed that Zangetsu has multiple forms, in his regular form he may take on the appearance of an older more masculine man, but in his Bankai form Zangetsu appears much younger, closer to Ichigo's age, with shorter hair, lighter skin, and wearing a hooded trench coat. In this form he does not answer to the name Zangetsu, but says that he has taken on the name of Ichigo's bankai, Tensa Zangetsu.
Bleach: The Diamond Dust Rebellion
The 2nd Bleach movie. A valuable artifact known as the Kings Seal was stolen while Hitsugaya was transporting it. The Ohter captains believe Hitsugaya stole ...