Park Jungsoo: smart, introvert, conventional, president of science club and member of school’s youth Red Cross organization.

Kim Heechul: popular, lazy, leader of “Jjinbbang”, member of music club.

Kim Youngwoon: smart, outgoing, clingy to Jungsoo, transferred at 2^nd semester from another school.

Lee Hyukjae: smart, Jungsoo’s childhood friend but they went to different schools before and met again in high school.

Lee Sungmin: good friend with Jungsoo but secretly jealous of him, vice-president of science club.

Cho Kyuhyun: naturally annoying, member of music club.

Lee Donghae: member of school’s youth Red Cross organization.

Kim Ryeowook: member of school’s youth Red Cross organization.

Kim Jongwoon: member of school’s youth Red Cross organization.

Henry: member of music club.

Hangeng: member of Jjinbbang, Heechul’s best friend.

Kim Kibum: member of Jjinbbang.

Choi Siwon: Math teacher, science club mentor.

Shin Donghee: leader of “Haneure”.

Zhoumi: member of Haneure, had once lost to Jungsoo in president of science club election.

Moon Chaewon

Yoon Eunhye

Jung Yunho

Kim Jaejoong

Kim Junsu

Shim Changmin

Lee Hongki

Jang Geunsuk

Lee Jinki

Lee Taemin

Yoochun

Kangta

Jung Ilwoo

etc (possibly more TBA later)