Hyakunosuke Ogata is the former Superior Private of the 7th Division and a member of Hijikata's Group. He is the son of the major general of the 7th division and is an excellent sniper. He later joins Sugimoto's group, but his exact goals are unknown for a long time. His favorite food is monkfish stew.

Ogata is a very cold-blooded person, who doesn't seem to trust anyone but himself. He doesn't hesitate to kill others and feels no regret or pity, which he himself points out as characteristics a sniper should have. He will remain his cool during a fight, but if his chances of winning are low, he rather escapes than jumping into a fight he can't win. Even though he is quite emotionless, he does not like to be questioned, since has his own understanding of pride. In his opinion all people have to be ruthless killers like him, or else they "should not even exist." On the surface he seems polite, but is also able to deceive others.