Characters:

Lu Han (Xiao Lu)

He has a huge crush on one of the school's most popular guys: Kim Jongin. He's an outstanding student but has a shy personality. He wishes to send a love letter to Jongin but constantly fails in his drafts. His drafts, however, become diaries that will soon be in Oh Sehun's possession. To say that he loathes Sehun would be an understatement. 
 

Oh Sehun (the Devil)

He is Jongin's best friend and one of the school's most popular guys as well. He just broke up with his ex when he found Luhan's diary. He uses the secrets he discovered t his advantage, and make Luhan's life a living hell.

Kim Jongin

One of the school's most popular guys, Sehun's best friend and Luhan's crush. He has been courting, and rejected, by the student council president, Kyungsoo, for two years.
 

Do Kyungsoo

The president of the sudent council. Jongin's love interest and Lu Han's cousin. He adores Lu Han, and has a strange friendship with Byun Baekhyun. The two often comepte for Luhan's 'love and attention.'

Byun Baekhyun

The school's sassiest diva and Luhan's best friend. He is dating Park Chanyeol. He has a strange friendship with Do Kyungsoo. The two often compete for Luhan's 'love and affection'
 

Park Chanyeol

One of the school's most popular guys and a close friend to both Jongin and Sehun. He is the boyfriend of the school's sassiest diva, Byun Baekhyun.