Sayoko

小夜子 Voiced by: Rie Ishizuka (Japanese), Anastasia Muñoz (English) Mikuni's protector and doctor. Originally a doctor of the Tokyo University Hospital, she was summoned by the Atlas government to be an educator to Mikuni. In order to designate Mikuni as the legitimate successor of Atlas, she took great efforts in the development of the medicine for her disease and also exposed herself to danger. She watches in delight as Mikuni sees through the lies of people and puts them to death. She also experiments on people to her delight and loves to be insulted by them while she does it. At one point, Momoko refers to as a sadist. She used to be prejudiced against Miiko initially but as time passed, she acknowledged Miiko as a comrade. She tries to end her live to enable Mikuni to become the successor of Atlas but is rescued by Momoko. It is later known that she had a daughter who died from the same disease that Mikuni has and Mikuni reminded her of her. Shogō Kudo is also revealed to be her half-brother.