Kokoa Shuzen is the younger half-sister of Moka Akashiya and the fourth sister of the Shuzen Family. She arrives as a first-year student to Yōkai Academy. Like her sister, Kokoa is also a Vampiress, but her powers are not sealed. Being younger, Kokoa is not as strong as the 'sealed' Inner Moka, but in spite of this she is able to carry the Transformer Bat, named Kou (also named Koumori Nazo and Kou-Buddy (Kou-buddy being the English dub version of "Kō-chan")), which she was going to give to Moka for her tenth birthday. It was too heavy for Moka so she passed it up. Kokoa kept it, and is able to wield it herself with enough strength to make herself formidable.