Michiaki Sakaki

Yumiko's dad is the big shot of the Tohin Railway Group and runs Mihama Academy. When his wife had Yumiko instead of the son he wanted, he was pretty bummed out. Despite his wife's health issues, he ended up having a son with a mistress, which tragically pushed his wife to suicide. That son didn't last long either, falling ill and passing away. Feeling guilt and loss, he decided to take Yumiko under his wing, grooming her as the family heir. After a wild incident where she attacked a classmate with a box cutter, he whisked her away to Mihama Academy, keeping her hidden from the world.