Kim Sangha - Proud school bully, and rival to Yoo Jicheol's daughter, Youngson.
2. Top Management
Eunbin - Member of girl group Apple Mint.
3. Somehow Family
Sung Haneul - She secretly came back to korea for an unknown reason and now has Aphasia. She is the daughter of Sung Dongil and Jin Heekyung.
4. DODOSOSOLALASOL
Jung Gayoung - Jun's friend from highschool, she returns and causes problems for Rara and Jun's relationship. (Eps 13-15)
5. Dear.M
Min Yanghee - 'Goddess of Engineering'. She can be oblivious but her charms make her impossible to hate.
6. Youth of May
Yujin - Hwang Heetae's ex-girlfriend who suddenly asks him to get married. (Ep 1)
7. At a Distance, Spring is Green
Wang Youngran - A fourth-year student in the physical education department. 'The queen of Myungil University’s dorms'. She is a longtime friend of Nam Soohyun.
8. Duty After School
Yeon Bora - Easygoing and Hot-Tempered. Although she may seem harsh, she cares for her classmates in her own way.
9. Hierarchy
Yeji - A student at Jooshin High School where the top 0.01% control everything. A friend of Hera’s who always knows how to add the fun to any situation.
10. I Love You Bit By BIt
Jeongmin - An NCO sergeant. She was college sweethearts with Cha Woori before he asked to break up. 2 years later, she met him again unexpectedly in the same unit as his superior.