The Tō strategist and Tōtaku's best childhood friend. In the first VN Tōtaku was rumored to be an oppressive leader, which caused the campaign against the Tō faction. After the Tō faction fell to Kazuto, it's revealed that the rumors are not true, and Kazuto decides to spare Kaku and Tōtaku. Since no one has seen their faces, Kazuto hires the two to work for him as maids while at the same time he sends out words that Tōtaku has been executed in order to avoid suspicion from the alliance.
She cares for Tōtaku dearly and is at first against Kazuto getting familiar with them, but Tōtaku gradually opens up to him and Kaku cannot say no to her. She eventually develops some interest in Kazuto, but puts up an extremely tsundere front to conceal it.
It is later shown that her harshness is mostly a result from her forgetting own happiness to devote herself to protect Tōtaku.