Some articles on zangetsu:
Bountos - Non-Soul Reapers - Zanpakutō Spirits - Zangetsu
... Zangetsu (斬月?) is a Zanpakutō owned by Ichigo Kurosaki, originally appearing a tall man with ragged black hair, facial hair, and sunglasses that Ichigo visited within his inner world ... While under the influence of Muramasa, Zangetsu attacked Ichigo managed to free Zangetsu from Muramasa's control with the help of his inner Hollow ... During Ichigo's battle with him, his Inner Hollow proclaimed him as Zangetsu himself ...
... Zangetsu (斬月?) is a Zanpakutō owned by Ichigo Kurosaki, originally appearing a tall man with ragged black hair, facial hair, and sunglasses that Ichigo visited within his inner world ... While under the influence of Muramasa, Zangetsu attacked Ichigo managed to free Zangetsu from Muramasa's control with the help of his inner Hollow ... During Ichigo's battle with him, his Inner Hollow proclaimed him as Zangetsu himself ...