Koshinori Yagyuu

Koshinori is image-conscious and proud of the Yagyuu family's position. He cultivates what he considers the appearance of an aristocratic celebrity, even carrying a cat despite being allergic to it because he believes doing so makes him look distinguished.

He is also particular about how Kyuubei Yagyuu addresses him, preferring more affectionate forms such as "Papa" rather than an overly formal fatherly title. This comic vanity contrasts with the severe expectations his household historically places on its heir.

Koshinori nevertheless loves his child deeply. After Kyuubei's mother died following childbirth, he refused pressure to remarry because producing a male heir could have displaced Kyuubei. Instead, he chose to preserve Kyuubei's inheritance by raising her as the family's male successor, a decision he later recognizes imposed its own burden on her.

Koshinori belongs to a family renowned for swordsmanship and has training in the Yagyuu martial tradition. His role, however, emphasizes his position as head of the household more than frontline combat.

His authority extends over a wealthy samurai family with long-standing ties to the Bakufu. The Yagyuu estate maintains a dojo and retainers, including the elite Four Devas.

Koshinori's small stature is shared with other male members of the immediate Yagyuu line and does not indicate a lack of martial education.

Koshinori appears during the Yagyuu arc as the father of the heir at the center of the dispute involving Tae Shimura. His household supports Kyuubei's proposed union with Tae and becomes embroiled in the contest against the Yorozuya and Shinsengumi.

The conflict exposes the pressure surrounding the Yagyuu succession. Koshinori and Binbokusai eventually acknowledge that their efforts to protect Kyuubei's place as heir also forced an identity and set of expectations upon her. They become more accepting of Kyuubei choosing how to live.

Later appearances generally place Koshinori in comedic stories involving the Yagyuu household, its social prestige and his attempts to preserve an aristocratic image.

Kyuubei Yagyuu is Koshinori's child and designated successor. Koshinori's refusal to remarry was intended to protect Kyuubei's inheritance, although his solution of raising her as a male heir created a different form of pressure.

Binbokusai Yagyuu is Koshinori's father and the elderly patriarch of the family.

Tae Shimura becomes connected to the Yagyuu household through Kyuubei's desire to have her as a spouse.

Ayumu Toujou serves the Yagyuu household as leader of its Four Devas and as Kyuubei's devoted attendant.