Kai Miyagusuku
, 宮城 カイ
Sayas took on the role of an "elder" brother after adopting a former classmate who had stopped playing baseball just before Sayas' arrival at school. This individual was once well-regarded as both a student and athlete but had been getting into more altercations at school in recent times. The death of his father forced him to confront the responsibility of keeping his family together, which proved challenging for him. He struggled with accepting that Saya and Riku were not human, causing him great turmoil.
When George is kidnapped, Kai steals his fathers M1911 pistol to try to rescue him. David confiscates it, but later returns it to show that he feels K
As he finally comes to terms with both, Riku is raped and killed by Diva, and Saya disappears for a year. As the last surviving family member of Sayas
After Saya kills Diva, he is able to convince her to continue living, and prompts Haji to "disobey" Saya and confess his own love for her. Saya and Ka
