Kai is of the Oina Tribe in Kamui with the ability, like all half-beast Oina to turn into a wolf and wears a deer mask at all times. In wolf form she is brown with a light underbelly and is one of the few Oina able to safely travel through Yoshpet the forest of confusion. This is due to having become lost when she was younger but was rescued by Issun and gradually became increasingly familiar with the forest as she regularly visited the poncles.
Her little sister Lika had mysteriously disappeared when the twin demons stirred and Kai feared they had taken her. She also seems to advocate for Oki and support him in having taken the sacred sword Kutone.