Mayuri Hanyu

A female cosplayer and one of the Four Heavenly Kings. She became a teacher at the same high school as Masamune and others as a new graduate in the spring when Lilysa entered high school, at the age of 22. She teaches home economics. Although she has a large bust, those around her refer to it as "demonic bust" implying more than just its size.

She mainly cosplays as the fighting game character Rastalotte, and at events, she sells homemade ROMs featuring risqué costumes. She met Lilysa at an event venue during middle school, and the middle school where she did her teaching internship was the one Lilysa attended, so they have had various connections since then.

She went to university on a scholarship and was called one of the Four Heavenly Kings during her student days. However, she secretly quit cosplaying and chose the path of teaching, feeling guilty about it because she needed to repay her scholarship. Fearing the risk of not being able to continue as a teacher if her past as a famous cosplayer who also produced risqué ROMs became public (making it difficult to repay the scholarship), she hid her past and became a teacher, extremely disliking any public mention of her past. She particularly pressured Masamune, who had one of her ROMs, to keep quiet.

Although initially she refused Masamune's request to become an advisor, she eventually accepted the role of manga club advisor after realizing that Masamune had discovered her true identity as Mayura, and because the club involved cosplay and Lilysa was a member. As a manga club advisor, she submitted activity reports for the school, returned to cosplay once for Lilysa, provided various guidance and advice on cosplay, accompanied the club on a training camp as a supervisor, and even indulged in fighting games with Masamune and others in the manga club room (she is quite skilled at fighting games), thus supporting her students as a manga club advisor.

She shows signs of being romantically interested in women, as evidenced by her nosebleeds and excitement at seeing Lilysa and others in cosplay.