Katsuhito Kariya was a patient at Haibara Hospital with an advanced case of Luna Sedata Syndrome. He could not recognise his own face due to the illness. Since childhood, he has suffered persecution mania, and in his time at the hospital, he became convinced that the hospital was conducting experiments on humans. Katsuhito most likely died on the Day Without Suffering, when Sakuya Haibara passed on Blooming onto him.