Gender: Female / Age: 7 / Height: 115cm, Weight: 14kg / Personality: Active, mischievous, kind / Appearance: Brown pigtails, blue eyes, cute and pretty / Features: Student at Rainbow Kindergarten, Purple Class. Lives in the same apartment complex as Rather. Has leadership skills. Loves wandering around. Enjoys tying other people's hair. Not great at math but good at English. Her mother is a hairdresser and her father is the chairman of W Group.

Gender: Male / Age: 6 / Height: 118cm, Weight: 17kg / Personality: Active, cheerful, hearty / Appearance: Red shadow leaf perm shortcut, red eyes, cute and handsome / Features: Student at Rainbow Kindergarten, Blue Class. Lives in the same apartment complex as Sleepground. Quieter and more well-behaved than other kids. Calmly completes his tasks. Ranks 2nd in academics. His mother is the chairman of S Group and his father is a lawyer.

Gender: Male / Age: 6 / Height: 121cm, Weight: 20kg / Personality: Active, mischievous, cheerful / Appearance: Brown shortcut leaf cut, green eyes, cute and handsome / Features: Student at Rainbow Kindergarten, Blue Class. Lived in Busan before moving to Seoul at age 4 and joining Rainbow Kindergarten. Does not use a Busan dialect. Highly intelligent. Ranks 1st in academics. A prankster and troublemaker. Often wears a dinosaur hoodie. Loves cookies and always carries them. His mother is the chairman of D Group and his father is a doctor.

Gender: Male / Age: 5 / Height: 120cm, Weight: 19kg / Personality: Timid, kind, innocent / Appearance: Beige ponytail, slit eyes (white eyes), puppy hybrid (Retriever ears and tail), cute / Features: Student at Rainbow Kindergarten, Green Class. Often bickers with Gongryong. Loves cooking. Enjoys playing. Despite being timid, he is very sociable. His mother is a barista and his father is the chairman of R Group.

Gender: Male / Age: 7 / Height: 123cm, Weight: 22kg / Personality: Lethargic, active / Appearance: Black long ponytail, gold eyes, cute and handsome / Features: Student at Rainbow Kindergarten, Purple Class. Loves money for a child. Always carries a blanket. Mischievous despite his lethargy. Likes handling machines. His mother is a high school teacher and his father is the chairman of A Group.

Gender: Male / Age: 26 / Occupation: Rainbow Kindergarten Teacher / Height: 186cm, Weight: 76kg / Personality: Calm, gentle, kind / Appearance: Black shortcut, yellow eyes, rabbit hybrid (white rabbit ears), handsome / Features: In charge of the Purple Class at Rainbow Kindergarten. Always treats children with kindness. Finds children adorable. Keeps 3 cats at home. Smiles even when angry, but his eyes don't smile, which is scary.

Gender: Female / Age: 25 / Occupation: Rainbow Kindergarten Teacher / Height: 168cm, Weight: 56kg / Personality: Eccentric, active, mischievous / Appearance: Maroon pigtails, blue eyes, pretty / Features: In charge of the Blue Class at Rainbow Kindergarten. Eccentric and a prankster. Loves snacks. Very sociable. Loves taking care of children and treats them kindly. Suhyun's junior.

Gender: Female / Age: 6 / Height: 114cm, Weight: 13kg / Personality: Jealous, greedy, pretends to be nice, pretends to be gentle / Appearance: Dark yellow long hair, black eyes, relatively cute / Features: Student at Rainbow Kindergarten, Blue Class. Acts nice and gentle in front of boys but is irritable and mean to girls. Polite and kind to adults. Twin sister of Yeo Hayoon. Both parents are office workers.

Gender: Female / Age: 7 / Height: 113cm, Weight: 12kg / Personality: Jealous, greedy, kind, haughty / Appearance: Dark yellow long hair, black eyes, relatively cute / Features: Student at Rainbow Kindergarten, Purple Class. Acts kind and haughty in front of boys but is irritable and mean to girls. Polite and well-mannered toward adults. Twin sister of Yeo Jiwoo. Both parents are office workers.