Saitou Hajime

Saitou Hajime （斉藤一） is the assistant vice-captain of the Mibu-Roushi (later the Shinsengumi). He is later promoted to captain of the Third Troop.

Early Life
Saito Hajime was born Yamaguchi Hajime. The child of a lowly bafuku samurai who slowly increasd his rank until he was directly under his boss, Saito was born and raised in Edo. When he was 19, a friend challenged him to a sword fight, to which Saito accepted. Though Saito did not intend to win, he ended up killing his friend. Though he expected to have killed in return, his father told him to run away, as he was still the son of a bushi. Saito then changed him name and went to Edo.

Skills & Personality
Saito is one of the strongest swordsmen of the Shinsengumi, rivaling the skills of Okita Souji. His cool and calm demeanor earns him the admiration of the members, not knowing that he also has a snarky side (usually expressed in his "mental notes" and "inner voice") which is usually seen when he's around Souji. Nevertheless, he's considered as one of the most valuable members of the Shinsengumi.

Appearance
Saitou's appearance and voice bear a striking resemblance to Tominaga Sei's late brother Tominaga Yuuma, who was his comrade during his days at the Yoshida dojo in Edo. As a result, Sei looks up to him, fondly calling him "ani-ue" (literally meaning "brother above"), much to his dismay.

Work as a Spy
Most members of the Shinsengumi are unaware that Saito holds a secret job: that of being a spy for none other than Matsudaira Katamori, daimyo of the Aizu clan and the sponsor of the Shinsengumi, reporting to him directly about the recent events that are taking place within the group. Katamori himself stated that if it wasn't for Saitou's work behind the scenes, the Shinsengumi would've fallen apart sooner.