Naruto (manga)
Orochimaru's right hand and spy.  He is good at medical ninjutsu and can manipulate cells. Kabuto was initially a Foundation spy.  He had no memory of his past. Orochimaru helped Kabuto when Danzo did not trust him. Kabuto used his skills to spy on people for Orochimaru. After Orochimaru was defeated, Kabuto decided to master Snake Sage jutsu.  He put some of Orochimaru's remains into his body. He also added DNA samples of Sound Five, Jugo, Suigetsu, and Karin.  Kabuto perfected the Reanimation Jutsu. He made Tobi work with him as payment for his surfaces. Kabuto was defeated, but he saved Sasuke. After the war Kabuto returned to run the orphanage he was raised in with his adopted brother Urushi.