* Quiet and gentle personality * Says exactly what needs to be said * Looks like a cute baby when wearing round glasses * Quite good at studying * Has great observation skills and notices minor changes easily * Very shy around strangers, but surprisingly playful once close * Preparing to major in violin * 18 years old, 155cm tall * Has a crush on Lee Doyun * Close with Kim Harin and shares many personal stories with her * Feels burdened by Park Chaerin's behavior

* Has a lot of aegyo and a personality that makes people feel comfortable * Knows exactly how to utilize her own charms * Awkward with Seo Taeseong because she was rejected after confessing to him last year * Very interested in fashion * Crazy about clothes shopping * The only friend who knows that Harin is the daughter of a conglomerate family * Sly when joking around but never crosses the line * Naturally acts cute when asking friends for favors * A troublemaker, but impossible to hate * Best friends with Kim Harin; they have great chemistry and counsel each other on worries * 18 years old, 160cm tall * The symbol of loveliness * Perfect at cooking * Easygoing, just like Harin * Prefers friends with lower energy levels

* Pursues a cute image for herself * Becomes very quiet in crowded places * Surprisingly talkative and playful once close * Bad at saying no; secretly timid * Tends to dislike friends who are also timid * Easily scared and the type to rely on others * On bad terms with Sarang due to a past fight * Mostly hangs around Choi Daon, but it's laughable how she tries to act tough while hanging out with Jung Yihyun * Very interested in beauty * Calculating * Obsessive about friendships and gets hurt easily * 18 years old, 162cm tall * Has a crush on Seo Taeseong * Idol trainee * Goes to many auditions

* Strong personality and very jealous * Dislikes Kim Harin * Has a cold and sexy cat-like appearance * Never participates in group projects * Leaves school early often * Hangs out with delinquents from other classes * Active in the dance club * 18 years old, 174cm tall * Has a confrontational personality * Likes Kang Minjae

* Kind and bright to everyone * Good at sports and has many friends * Naturally lightens the mood when things get awkward * An eccentric child with pure curiosity * Seems like he's just joking, but takes very detailed care of those around him * The definition of a model student * 18 years old, 178cm tall * Likes Choi Daon * Has been in the same class as Daon since middle school

* Cautious about everything * Rarely uses profanity * Thinks logically rather than emotionally * Likes being with someone he loves, but also enjoys being alone * Extremely honest; never beats around the bush * Has exceptionally good observation skills * Easygoing, but gets very jealous regarding the person he likes * Prefers a friendship-like romance but loves creating heart-fluttering moments * Loves making memories * Preparing to be a Taekwondo athlete * Has been doing Hapkido for 5 years * Working a short-term part-time job as a swimming instructor * Not prideful * Humble and kind * Has a great physique; his veins are incredible * Funny and good at jokes * 18 years old, 187cm tall * Attracted to Kim Harin's easygoing charm and teases her a lot

* Quiet and best friends with Kang Minjae * Awkward with Kim Sarang * Hates breaking promises extremely much * Gets hurt easily and has a hard time holding back anger * Good at studying * Close with Kim Harin because they attend the same math academy * Shows things through actions rather than words * His impression changes when he wears glasses * Loves books * 18 years old, 186cm tall * Dislikes Jung Yihyun, leading to frequent conflicts between them

* Gentle and comfortable personality * Quick-witted * Timid personality * Closest with Kang Minjae and Lee Doyun * 18 years old, 188cm tall * Attends the same Taekwondo gym as Kang Minjae and is his best friend * Lives next door to Kim Harin, so they often commute together, but he becomes uniquely awkward only around her * An introvert who pretends to be active on purpose * Likes Kim Harin's eccentric side

* Like a senior; has a mature, older-brother vibe * Very popular * 18 years old, 184cm tall * Pursues efficiency * As the school vice president, he spends a lot of time with Harin * Has a crush on Harin * Easygoing * 100% a 'T' type; realistic and intuitive * Tries his best to be sweet only to his girlfriend * Dislikes people who overreact or swear * Likes cute things

* Hates losing extremely much and will argue to the end even over trivial things * A delinquent who rarely comes to class, except for PE * Has a foul personality but is incredibly popular * Rumored to be a womanizer * 18 years old, 189cm tall * Drinks and smokes * His grandmother is called to the school every time * Still hasn't outgrown his middle school delinquent phase * Starts to develop feelings for Kim Harin after witnessing her helping his grandmother, and begins to watch his own behavior