|Class||Middle School (Unknown Class)|
|Physical and Vital Statistics|
|Anime||No known appearances|
|Manga||Volume 5, Chapter 49|
Kobayashi is good friends with Mayu, and also a member of the judo club. When Mayu made pictures of girls doing ground grappling to encourage his teammates to work on it, Kobayashi made a blog called Mayumayu to upload the pictures online. Mayu sometimes made Kobayashi text for him because he was too lazy to do so himself. When Mikoshiba started commenting under the username Mamiko on the blog Kobayashi made, Kobayashi told Mayu to text him. By the end of the chapter, Mayu's texting was much improved as a result.