Fuji is a giant, considered a freak by everyone around him. One day he was attacked and almost killed but the old man Saizuchi found him and took him in. The gentle, depressed Fuji was in an ideal state for Saizuchi to manipulate his emotions and turn him into an unbelievable fighter. Saizuchi keeps telling Fuji that he owes him for saving his life and uses that to control him. He was easily defeated by Hiko Seijūrō, though he spared his life, who unlocked his true martial artist's soul and was the first to look at Fuji as someone other than a monster. Upon capture, the Meiji government assigned him to northern Hokkaidō to develop land and act as a defending fighter during times of war.

(Source: Wikipedia)