A tall, bespectacled, fearsome-looking student with noticeable scar extending across his forehead and left eyebrow. When first introduced, he became a hikikomori a week after he got into trouble with a gang. Adachi and Shinigawa beat the gang (without knowing they themselves were the cause of his self-isolation) which allows him overcome his fears. When they forget about him, he is shattered again. Adachi tries to get him to attend school and take the exams, but he refuses, saying he is afraid of sitting next to Shinagawa. But Shinagawa realizes that Chiba is merely looking for Adachi's attention, and tells him to attend school and take the exams or she will never visit him again.
Chiba is very smart and rich, and his mother is young and beautiful. He has a habit of unknowingly glaring at people which often cause a misunderstanding. He is very smart and almost always scores 100 marks for his tests, except for one occasion in chapter 67, where it is shown that he scored 94 marks on a math test, two marks lower than Shinagawa. In later latest chapters, it is shown that he has a crush on Makoto which seems obvious to everyone around him, however Makoto doesn't seem to have noticed yet but after the timeskip, they shown as a couple
Chiba is a tall, bespectacled, fearsome-looking, slim student with spiky black hair and glasses and very noticeable scars. He wears a dark-colored long-sleeved shirt under a light-colored sweater, dark-colored pants and a pair of simple shoes.
When first introduce, Seiya had a very shy personality up to the point, he didn't go to school for 4 months. He gets very weird ideas as when Daichi and Hana ate his dinner, thinking they wanted kidnap him and hold him ransom. He refers Daichi as a gangster. After some time, he started coming to school. Daichi notices he just wants Hana's attention.
- Yankee-kun to Megane-chan Manga: Chapter 3,Page 6
- Yankee-kun to Megane-chan Manga: Chapter 3,Page 14