Mitake is the fiercely loyal retainer and strategist serving Habaki Kagimura within the Rokki-dan. He analyzes the Ittō-ryū, identifying its core membership. Mitake attends pivotal moments alongside Habaki, including witnessing the suicide of Habaki's wife and child. He actively hinders the Ittō-ryū, sabotaging their horses at stations to slow their advance. During one mission, he discovers the wounded Ryo Soma after her battle with Koji Kashin and new recruits. Acting on Habaki's standing order to protect her, Mitake decides to return Ryo to her father. Despite Ryo's protests about Habaki's motives, Mitake insists she represents Habaki's sole remaining connection. When Ryo escapes near Giichi and Hyakurin, Mitake retrieves her and accompanies them to their lodging. He expresses doubts about the Rokki-dan defeating the Edo Palace attackers, suggesting Giichi might be the only one capable of stopping Anotsu should he survive.

Mitake participates in the Rokki-dan's violent operation at Nakaminato port, obeying Habaki's command to kill everyone aboard encountered ships. He curtly decapitates questioning government officials. Later, during the Ittō-ryū's arrival, Mitake, alongside Tarieshin Hasshu and Shinhei Doma with Hebigumi support, receives orders to eliminate Makie Otono-Tachibana. Witnessing Makie deflect Hebigumi attacks, Mitake warns his comrades. In the ensuing fight, Makie disarms Mitake and redirects his boomerang blade into his shoulder. After Makie kills Doma and then Tarieshin, a disarmed Mitake pleads with the arriving Giichi to kill Makie. Makie responds by severing both of Mitake's arms.

Mitake's relationship with Habaki is defined by unwavering loyalty and service. Following Habaki's execution, Mitake is entrusted with taking Ryo Soma in as his ward, fulfilling Habaki's final trust. His interactions with Ryo involve executing Habaki's wishes for her safety, despite her resistance and skepticism regarding her father's motivations.