Kotoha gave birth to Inosuke at the age of 17 or 18 and was in an abusive relationship with Inosuke's father, as well as with her mother-in-law who bullied her on a daily basis. One day, during one of his outbursts, she bit her husband's hand, grabbed Inosuke then ran away from the abusive household, fleeing barefoot through the snow. Since she didn't have parents or any siblings to go to, she was running ahead until she reached the Paradise Faith cult, taking shelter as one of the worshippers of Doma - a leader of the cult. Her husband and his mother chased her there but were soon killed by Doma, who found them to be too noisy, abandoning their corpses in the mountains.
She lived there happily with her son until she suspected that the worshippers were being eaten by Doma. After accusing him of lying to his followers, she ran from the temple with Inosuke in her arms and tried to go through the forest, but was trapped by a cliff. In her final moments, she apologized to Inosuke for failing to protect him and tosses him into the river as an attempt to save his life. She was ultimately killed and eaten by Doma, who claimed to have devoured her to the bone