Katamori Matsudaira governs the Aizu domain as feudal lord and commands the Kyoto Military Commission, directing the Shinsengumi to enforce order in Kyoto amid rising turmoil. Following the near-destruction of the Shinsengumi’s Eighth Division by the Masked Demons, he launches a covert operation to replace fallen captains with eight condemned criminals, offering them redemption in exchange for adopting the identities and responsibilities of the deceased leaders. His pragmatic strategy sustains the Shinsengumi’s operational strength while gambling on the convicts’ untested loyalty.

He governs from the Konkai-Komyoji Temple, the Aizu domain’s strategic headquarters, where he confronts rampant lawlessness and anti-shogunate factions endangering Kyoto’s stability. After the substitute Shinsengumi’s reputation falters during the Shirakawa residence incident, he issues a stringent three-day ultimatum to restore their standing or face dissolution, prioritizing the group’s symbolic power as a deterrent against rebellion.

His tactical acumen emerges in his scrutiny of the Masked Demons, linking their masks to Noh theater traditions, suggesting a cultural thread underlying their menace. Though doubtful of the replacement unit’s efficacy, he entrusts operational command to Heisuke Toudou, concentrating on political strategies to neutralize threats such as Kogoro Katsura’s imperialist schemes.

Within the series, his narrative centers on political and military duties, devoid of personal backstory, framing him as a shrewd leader maneuvering through the Bakumatsu era’s chaos. His actions prioritize authority and stability, employing unorthodox tactics to balance order with the Shinsengumi’s covert reinvention.