Itou serves as an advisor to the Shinsengumi but is later exposed as a traitor whose ambitions were exploited by Takasugi to dismantle the group from within. Viewing himself as Hijikata's rival, he succeeds in getting Hijikata suspended from the Shinsengumi and even attempts to assassinate Kondo. However, his plans are thwarted by the Shinsengumi members and Yorozuya. After losing his left arm and being defeated by Hijikata, Itou comes to understand the significance of the bonds he formed within the Shinsengumi and regrets his betrayal of his close friends. He is granted one final duel with his old rival and dies honorably as both a friend and a warrior.
Itou's character is loosely inspired by Itou Kashitarou of the historical Shinsengumi.
