Muramasa's True Identity Revealed
After Kouga's defeat, Muramasa becomes unstable, as he had absorbed hollows in order to sustain himself without a master. Many hollows spill forth from his body, and he transforms into a form similar to an Arrancar. Orihime tries to reach out to him to save him from his sorrow, but he attacks the group. Ichigo manages to slash through Muramasa, but he becomes even more unstable and becomes a larger dome-shaped mass, engulfing him in the process. The formerly rebellious Zanpakuto return with their owners to help Ichigo and his friends in the battle.
Aired 12/01/2010EP 253 - Muramasa's True Identity Revealed
Bleach
Ichigo Kurosaki is a rather normal high school student apart from the fact he has the ability to see ghosts. This ability never impacted his life in a major way until the day he encounters the Shinigami Kuchiki Rukia, who saves him and his family's lives from a Hollow, a corrupt spirit that devours human souls.
Wounded during the fight against the Hollow, Rukia chooses the only option available to defeat the monster and passes her Shinigami powers to Ichigo. Now forced to act as a substitute until Rukia recovers, Ichigo hunts down the Hollows that plague his town.