|Romanized Name||Katase Mayoi|
|English Name||Mayoi Katase|
Mayoi is very savvy with electronics and is almost never seen without her lab-coat. She loves to tease Tsumiki with a passion, which often brought her severe repercussions from the latter. She is also a very sneaky person with a rather twisted sense of humor. She is very fond of games and competition (though she mostly loses due to some strange mishaps) and she's always into teasing others, just like Sakaki.
Mayoi has a knack for inventing (usually strange) devices to assist her with her antics. Her jokes often backfire on her, resulting in her taking damage and/or foiling the prank.
She does not like showing her eyes, as in an episode when she was asked to show her eyes. In response, she showed the asker a 'double fringe'.
Mayoi has bright orange hair and two buns on each side of her head, with bangs covering her eyes, so she could be blind. She is usually seen wearing her school uniform and her lab coat covering it. Her mouth is cat-like, as she seems to have a split lip. Mayoi's eyes are never shown, both in anime and manga versions. In anime, it is revealed that Mayoi wears orange striped bloomers under her skirt and lab coat.
In manga, Mayoi is noticeably shorter than in anime, much like other characters.
- Tsumiki Miniwa - Close friend and classmate. Mayoi would often tease Tsumiki about her crush on Io, which, more often than not, would earn her a devastating blow from the former. However, they both care about each other and are seen hanging out.
- Io Otonashi - Io is Mayoi's classmate, whom she always teases because of Tsumiki's less-than-subtle crush on him. He does not seem to mind her antics, though he did hit her once when she lazed off during the group's study time at his house. Apart from casual chatting and teasing, Mayoi has never displayed any other interests in Io.
- Hime Haruno - Mayoi's antics would often cause either physical or mental harm to Hime, though they both enjoyed each other's company. Despite her pranks, Mayoi seemed to care a lot about Hime, as with any other friend of hers, as when Hime forgot her umbrella at home, Mayoi would offer Hime her spare umbrella.
- Sakaki Inui - Sakaki is almost always the fellow conspirator in Mayoi's schemes, though their plans would occasionally backfire and hurt him. They both quite enjoy teasing Tsumiki and Io as a couple. Some of Mayoi's pranks regarding Sakaki cause him humiliation and/or pain when they don't turn out well, though this is likely unintentional, as sheholds no ill will towards him.
GalleryEditAlso look under the Mayoi image category.
- Mayoi has the habit of adding "-nya" to the end of her words.