Kana Tatebayashi

This half-mermaid, half-vampire youkai is a five-year-old child under Shidou's protection following a mysterious incident involving their parents. Her unique nature means her bloodline leans toward vampiric, and consuming blood causes her body to mature rapidly into a teenage form, notably developing large breasts unlike her twin sister Mina. She possesses a gentle and apologetic demeanor, often deferring to Mina's behavior.