Heroine / Kim Sun

-kind, friendly, has musical talents, tough

-new star member/the only female member of the MMA club, has black belts in judo & taekwondo

-lives away from family, hence has part-time job after school and busking for a living during weekends

Kim Young Kwang 

-warm, helpful, hardworking 

-star of soccer team

-partners with heroine at his weekdays’ part-time job

Ahn Jae Hyun

-cold, cynical, loyal

-star swimmer

-next-door neighbour to heroine

Lee Soo Hyuk

-aloof, quiet, mysterious

-star basketball player

-often meets heroine at bus stops/while in the bus

Kim Woo Bin

-dedicated, looks beastly (but still handsome), has hidden artistic talent

-star chef in home economics club

-heroine often urges him to show his hidden talents (singing, poetry)

Lee Jong Suk

-loyal, detailed, most naïve

-best beautician in beautician club

-often quietly assists heroine any way he can, e.g gives up his seat so heroine can learn better in class, using his cuteness to beg their crazy fans to leave her alone and etc,

Hong Jong Hyun

-quiet, introverted, studies genius

-biggest brain in mechatronics club

-only shows his boyish/playful side