Summary
Diva serves as the primary antagonist of the narrative and is the twin sister of Saya. Born in 1833, she was subjected to an experiment that required her to be confined in an isolated tower from birth. This seclusion resulted in a childish demeanor, social ineptitude, and a complete ignorance regarding the moral consequences of her behavior. Diva is the source of Delta67, a substance derived from her blood that enables humans to transform into Chiropterans. Her isolation fostered a deep hatred for Joel, which manifested violently when Saya freed her; she subsequently slaughtered Joel and all the guests attending his birthday party.
