Kim Hyoyeon
16 y.o. Shy at first, but friendly and crazy if you know her. Clumsy, noisy and talkative. She's Jungah, ParkBom, Jinah and Sunkyu bestfriend. She's a fujoshi, and often read a fanfiction with Jinah and Jungah(it's a secret!)

Lee Jongsuk
20 y.o. He's very shy and quiet. He's a college student who are learning to be a teacher. He's sports teacher. He's Woobin and LeeJoon (Changsun) bestfriend.

Kim Jungah and ParkBom
17 y.o. Both are seniors. Hyoyeon's bestfriends or more like a sister to Hyoyeon. Jungah is Jinki girlfriend while ParkBom is in love with someone. 

Im Jinah and Lee Sunkyu
16 y.o. They're Hyoyeon's classmates. Hyoyeon, Sunkyu, and Jinah always stick together at school. The others like to called them Trio Blonde. Sunkyu is Key girlfriend while Jinah is likes Herr Joon.

Lee Jinki
18 y.o. Jungah boyfriend. He's now in his last year at the school. He's really funny and noisy.

Kim Woobin
21 y.o. He's Jongsuk college friend. Same as Jongsuk, he's a sports teacher. He's obviously likes ParkBom

Lee Changsun (Leejoon)
20 y.o. He's a Deutch teacher. He is strict and disciplined, but also like to fooling around. He's also a teacher at Dance Club.