A cat from the beginning of the common route; he is the lover of Naki, a cat that is going to be sacrificed as food to the village's cats.
Not much is known about Keiju and Naki; their story will be shown to the player if they make the choice "Think about the sacrifice".
Keiju and Naki were lovers, both from Karou. One day, Naki is chosen as the new sacrifice in order to provide food to the villagers. Keiju is reluctant to this fate but Naki doesn't want to argue with the village's elder and sadly accepts his fate; Keiju feels desperate for not being able to protect his lover, when Naki suddenly asks him to eat him first. In the end, Keiju bites Naki's arm and eats his flesh.
A few days after Naki's sacrifice, Keiju is out of his mind and ill with the Sickness, missing his left eye and ear. He attacks Konoe's house, mad and desperate, but Konoe is able to take Keiju to the village's healer. It's assumed that Keiju died later on. When Konoe comes back to Karou, the whole village is destroyed by the Void and all the cats laying dead are missing arms, ears or legs, as the Sickness killed everyone in Karou.