Characters:

Bae Sue-ji:

Suzy is a 16-year-old girl who is described as a delinquent in Kumaneko High School, although she is not, and simply tries to stand up for others against bullies. She has a strong personality and sometimes loses her temper, but is really very caring when it comes to those she loves, such as her sister Ji-eun. Her parents died in a car accident and so she had to become responsible for her little sister. As a result, she has become more mature and practical than others her age. However, she is terrible at cooking, so she relies on Taecyeon to cook for her and her sister.

Once, Suzy did nothing but sleep in class for the 1st year of school, which causes other students to see her as a bad student. Now she does well her studies, only slightly poor in English. Ironically enough, it is later revealed that she can quite accurately understand English in conversation, which eventually causes her to start considering studying the language more seriously. Taecyeon calls her "Sue-shi". He's very protective of Suzy and doesn't like when other men get too close to her. Suzy loves Taecyeon very much.

Ok Taecyeon:

A 24-year-old English teacher who teaches at Kumaneko High School, Taecyeon is described as a "plain, glasses-wearing English teacher." Taecyeon is the only one who looked for Suzy when she ran away and ended up marrying her, supposedly only to help her and Ji-Eun. He is sometimes goofy and says he appreciates seeing Suzy's rare smile. He asks Suzy to help him with problematic students because of her strong personality, although he is a teacher and that isn't her responsibility. He has a calm and caring demeanor, and cares for young Ji-Eun more than Suzy does (according to her). He often gives Ji-eun candy for his hard work or just for being cute. Taecyeon cooks for the family and usually sleeps much later than the rest of his family because of his dedication to teaching. Taecyeon has numerous costumes for both Ji-eun and Suzy to wear, and often dresses them up for cosplay. Even though they are married, Suzy and Taecyeon sleep separately. He occasionally sleeps in Suzy's room, but only next to Ji-eun. Taecyeon isn't open about his past, but later in the story, it is revealed that Suzy was once in a gang.

His mother has died, and His father is a politician as revealed by Wooyoung. According to Wooyoung, Taecyeon was an excellent student, as expected from a person set to become the successor of his father. One day, however, he suddenly turned into a delinquent and left home. It is mentioned that Taecyeon was not close to his family to begin with, especially after his father's second marriage.

At first,Taecyeon holds no romantic feelings for Suzy. He marries her out of sympathy for her and Ji-eun, and he feels strongly that he shouldn't be "touching" her in case she leaves him for another man; which he would respect if she did. He slowly falls in love with her throughout the series, and only his decision to wait until she has graduated high school prevents him from touching her. He is extremely protective and possessive of Suzy.

Bae Ji-Eun:

Ji-eun is the 10-year-old little sister of Suzy. Ji-eun's personality is bright; she often makes people around her happy. Both Suzy and Taecyeon love her. Ji-eun views Taecyeon as a brother or a father figure. Taecyeon often gives Ji-eun candy for her hard work, or just simply for being cute. Though still very young, she often tries to defend her sister when anyone bullies her.

Ji-eun goes to school with her Middle school teacher Nichkhun, who is Taecyeon's best friend and neighbor. Ji-eun's nicknames Suzy "Ji-ah" or "Su-shi" and Taecyeon "Yeon-shi" 

Other Characters:

Nichkhun Buck Horvenjikul:

He is a happy-go-lucky guy who is Taecyeon's best friend as well as his neighbor. He is also Ji-eun's Middle School teacher and is one of the few people who know about Taecyeon and Suzy's marriage. Nichkhun takes care of Ji-eun a great deal (while Taecyeon and Suzy are being lovey-dovey), and also poses as Suzy's distant relation and guardian, which is their official lie to conceal the relationship between the two. He also tells Suzy about Taecyeon's past.

Kim Soo Hyun:

He is one of Suzy's classmates and has a crush on her. Although Soo Hyun doesn't know that Taecyeon and Suzy are married, he originally sees them together hugging, when Taecyeon was telling Suzy that her life was more important than their marriage ring.

Jang Wooyoung:

Wooyoung is Taecyeon's younger brother. He's also a student at Kumaneko High School. He's very popular among the girls at school. Though due to his cold and rude attitude, they call him "Ice Prince". Wooyoung originally didn't believe that Suzy is a girl. He finally believes it after seeing her underwear. He once tried to bribe or supposedly give Suzy money to live comfortably until she graduates, in exchange for leaving Taecyeon. However, she smacks it away and called him an idiot for thinking that she will leave him for money. Despite being brothers, Wooyoung and Taecyeon have different mothers, but they do talk to each other in polite terms. Since Taecyeon had left the family, Wooyoung had to take over his responsibilities. He also insults Taecyeon for becoming a teacher, claiming it's below his social status. Wooyoung admitted to his brother, Taecyeon, that he likes Suzy.

Stephanie Hwang:

Stephanie or simply Tiffany, is one of the students of Kumaneko High School. She's 17 years old. She recently transferred there from overseas. She is the daughter of a hotel mogul. She also constantly hitting on Taecyeon. It is implied that she was only doing so because she wanted to make Wooyoung jealous or show a reaction. She was "bullying" Suzy when she first arrived, but eventually became friends with her. She gives Suzy a makeover for a date with Taecyeon. She told Wooyoung that she would be leaving for America to marry someone that her father chose for her, but she didn't want that because she was really in love with him (Wooyoung). So she stayed in Korea with him. Even though she is supposedly dating Wooyoung, but had confronted him having feelings for Suzy. 

Park Jiyeon:

She is the Aunt of Suzy and Ji-eun. She wishes to take care of Suzy and Ji-eun since her work has become less busy. She is the younger sister of Suzy and Ji-eun's Mother.She wanted to take away Suzy and Ji-eun from Taecyeon so that the secret of their marriage will not be revealed. Jiyeon forces Suzy and Ji-eun to leave Taecyeon's apartment and live with her. She believes that Suzy and Taecyeon will grow apart since they won't be seeing each other as often. Se is relatively small for a girl and has a slim build, and she's extremely baby-faced; She looks as if she's still in high school even though she is 28 years old. Suzy has stated that she has spent time with her since she was a little girl, and in all the time that she's known her, her face hasn't changed. Despite her appearance, she is very strong, and is something of a legendary Judo practitioner.