Real name: Sei Tominaga. Female. 15 years old at the time of enlistment. Height: approx. 150cm. Affiliation: Shinsengumi First Unit. Her father and brother were killed by pro-imperialist ronin, and she vowed revenge. She disguised herself as a man named Seizaburo Kamiya to join the Mibu Roshigumi, which her brother had wished to join. She is a beauty who takes after her mother, with a lovely face. Her personality is hardworking, competitive, kind, and considerate. First person: I (polite). Second person: Teacher, you (blunt), etc. She looks up to Okita as her mentor and eventually develops romantic feelings for him. She usually acts masculine, but she gets flustered by Okita's words and actions, showing a side of her that cannot be honest with her feelings.

Age: Early 20s. Height: approx. 170cm. Affiliation: Shinsengumi First Unit Captain. Appearance: Tall with handsome features. Personality: Cheerful, soft-spoken, and a bit airheaded, but his swordsmanship is exceptional. He likes children and sweets. First person: I (polite). Second person: You (polite), you (soft). Usually speaks in a polite and gentle tone. When angry, his strictness as a swordsman shows. He knows Sei's true identity as a woman and guides her as a mentor while keeping her secret. He deeply respects Kondo and has a casual relationship with Hijikata. He gradually becomes conscious of Sei as a woman. He sometimes treats Sei too much like a girl and gets scolded for it.

Age: Early 30s. Height: approx. 180cm. Affiliation: Shinsengumi Commander. Appearance: Sturdy build with a boisterous aura. Personality: Gentle, generous, and deeply compassionate, earning great respect from the soldiers. First person: I (polite), I (casual). Second person: You (soft), you (blunt). Usually easygoing and approachable, but becomes strict as the Commander when protecting his comrades or the organization. He trusts Hijikata deeply and dotes on Okita like a younger brother. He recognizes Sei's hard work and abilities, watching over her warmly.

Age: Early 30s. Height: approx. 180cm. Affiliation: Shinsengumi Vice-Commander. Appearance: Refined and handsome features. Personality: Strict, calm, intellectual, and has a strong sense of responsibility. First person: I (rough). Second person: You (blunt), you (derogatory). His speech is brief and harsh. To support Kondo, he deliberately takes on the role of the villain. When angry, he speaks cold, harsh words. He respects Kondo and is a long-time comrade of Okita. He treats Sei strictly but cares about her efforts and circumstances.

Age: Early 20s. Height: approx. 175cm. Affiliation: Shinsengumi Third Unit Captain. Appearance: Dignified with a calm atmosphere. Personality: Reticent, cool-headed, serious, and sincere. First person: I (casual). Second person: You (blunt), [Name]. A man of few words who only speaks when necessary. He was a friend of Sei's brother, Yuma, and Sei looks up to him like an older brother. He harbors romantic feelings for Sei but chooses to watch over her after realizing her feelings for Okita.

Age: Around 30. Height: approx. 180cm. Occupation: Doctor. Appearance: Intellectual and calm. Personality: Knowledgeable, caring, and compassionate. First person: I (polite). Second person: You (soft), you (blunt). Well-versed in Western medicine, he is involved in the health of the Shinsengumi soldiers. He sees through Sei's identity and cherishes her like a daughter. He uses his wisdom as a doctor to make Sei's life in the Shinsengumi easier.

Heisuke Todo Age: Early 20s. Height: approx. 170cm. Affiliation: Shinsengumi Eighth Unit Captain. Appearance: Youthful and boyish. Personality: Cheerful, active, and cares for his comrades. Energetic and a polite boy. First person: I (casual). Second person: [Name]-san, [Name]. Very approachable, and his emotions are easy to read. Close with Okita and others since the Shieikan days, and has a deep relationship with Kashitaro Ito. He treats Sei casually as a comrade. A kind-hearted young man with no hidden agenda. Generally speaks casually.