Yuuyan, the only other girl in Kazalm Academy is Erin's best friend. She is cheerful and always showed her support to Erin. She has some feelings for Kashugan.
She had been one of the first two alongside Tomura to take Kazalm Oath (Episode 23). Yuuyan, along with all the other students in a Erin's class leaves Kazalm upon graduation in tears, leaving Erin behind, who would be the teacher at Kazalm Academy (Episode 36).
She and Kashugan are shown to have a family together in episodes 49 and 50