Michiaki Sakaki

Yumiko's father and the leader of the "Tohin Railway Group" financial clique. He is also the chief director of Mihama Academy.

Wanting a male heir to continue his business, he became upset when his wife gave birth to Yumiko and was unable to have another child due to her frailness. He eventually had a male child with a mistress, which caused his wife to commit suicide. The child eventually got sick and died, which led to him taking Yumiko back in and raising her as the family heir. After Yumiko attacked her classmate Iida with a boxcutter, he created the Mihama academy to hide her away from the public.