Kou is a guardian of the Castle in Parallel Paradise. She is one of the few characters to carry firearms in the manga (let alone Kia and her Grenades)

Kou is with Misa and Sakura when they notice the flare that Imari shot off. letting them know that she found the male. Later, Kou arrives with Misa and Sakura asking her if the male is her. Imari tells them the male is not here, the flare went off by itself. Kou says that Imari is acting strange asks Imari if anything is wrong, but Imari gets angry, tells them the male is not here, and to go home. Seconds later Kou kicks down the door asking them if they thought they believe it.

Kou along Leigh-Mary, Lumi, Misa, and Sakura watch Youta and Imari mate while naked.

Kou, Sakura, and Misa mate with Youta.

Kou leads Youta and Lumi through the castle. She says the Castle Guardians are doing this on Leigh-Mary's orders.

Kou, Leigh-Mary, and Sakura watching from a distance discussing the repercussions of revolting against the Empress. Kou shoots Yaruya's soul; is then immediately pulled into her mental mind-prison (or "mental cave").

Kou's sense of reason is taken away by Yaruya, which makes her crave .

Kou having lost all sanity ask Youta to mate with her: he mates with her until she passes out

Kou is carried by Imari and and Sakura to a place she can rest.

Kou, Misa, and Sakura show up to save Youta from getting killed by the Empress.

Kou tries to shoot Kokubo to buy time only to then be smashed by her. She is then carried away to safety by Sakura.

Kou is sitting with the other guardians and Youta coming up with a plan to kill Kokubo, she describes it as a twisted joke.

Kou and Sakura watch Youta and Misa mate. Then Kou decides to go mate with Youta thinking it will be their last chance.

Kou is riding a Bicorn with Misa and Sakura heading toward Meese. She comments she never thought she would ride; then asks if it is letting them ride because they are non-virgins, Sakura confirms this. They arrive later with Kou shooting a Karu saving a girl from being raped by them.

Later Kou and Sakura arrive in Reel on the bicorn with Kou immediately shooting a giant Karu in its head.

Kou and Sakura work together to kill the giant Karu. Later Kou, Sakura, Tia, Pinako, and Lilia discuss Lilia's encounter with the Blue Moon goddess. Kou dismisses it as a dream.