(Male) As his name suggests, he is a robot with four wheels and a storage-like compartment on his belly. There are a huge number of items inside the compartment. He is in class 4-3 of a Korean elementary school. He is very eloquent and helps Hyuk, who has no limbs, a lot. (He pulls his wheelchair and sometimes shows Hyuk his phone.) In the past, during a school lesson on growing a 'Praise Onion' and a 'Criticism Onion,' he was in charge of the Criticism Onion. He is still growing the Criticism Onion now, and although he curses at it, he cherishes it immensely.

(Male) He has black bowl-cut hair and wears glasses. He is in class 4-3 of a Korean elementary school. He is the most innocent and a model student in the group with Seo-jun, Hyuk, and Robot, but occasionally his perverted personality is revealed, and he often makes the mistake of letting his inner thoughts slip out of his mouth. He takes his friends' jokes well and empathizes with them. Do-yoon's uncle is a person who lives recklessly without following the law. (His friends always play by imitating Do-yoon's uncle.) Example: Playing 'Do-yoon's uncle getting dragged to the police station after touching a collapsed woman's chest while pretending to perform CPR.'

(Female) She has short hair and wears red glasses. She is in class 4-3 of a Korean elementary school. She is the class president of 4-3. She always helps the teacher with tasks frequently. She also studies well and is kind to everyone regardless of gender.

(Crayon or Crapus) She has black hair down to her shoulders, wears a blue headband, and wears overalls. Her gender is 'Crayon,' but she looks like a girl. Because she has six parents, she has six surnames, but since three are foreigners, she uses three surnames. She claims her gender is 'Crayon.' (She uses the Crayon-only restroom.) Although she is a Crayon, she simultaneously has XX chromosomes and wants to be a girl. She is in class 4-3 of a Korean elementary school. She is a shy and tearful female student.

(Female) She has an incredibly beautiful and haughty appearance. She speaks very little and is a fan of a singer named Charlie Peppers. She always wears AirPods and listens to Charlie Peppers' songs. She is good at delivering blunt facts.

(Male) He has sharp but unique hair and a cute appearance. He is in class 4-1 of a Korean elementary school. He speaks his mind without hesitation. He also has a personality that digs deep until the end if there is something he doesn't understand. He talks a lot of nonsense or jokes, but sometimes he flusters others with sharp 'fact attacks.' He also has an innocent side and is somewhat thoughtless, so he uses profanity or sexual jokes without hesitation. Because of this, he is occasionally scolded by teachers. He is best friends with Do-yoon, Park Robot, and Jung Hyuk, and they made their own hideout to play in after school.

(Female) She has a black bob and a plain appearance. She is in class 4-3 of a Korean elementary school. She dislikes men and despises them. (Especially Yoon Seo-jun.) On the other hand, she is very kind to girls and has the strongest leadership among them. She utterly despises Kim-Bak-Choi Su-yeon and says hurtful things like, "Aren't you just a man?" She used to be close with Mina, but as Su-bin's words crossed the line more and more, Mina eventually exploded in anger and cut ties with her. She mostly uses phrases like "What?!" or "Ha, how ridiculous." She likes Yoon Ji-woong, but because she hates it being obvious, she acts like she dislikes him.

(Male) He has a two-syllable name, yellow buzzed hair, and a round appearance. He is in class 4-3 of a Korean elementary school. He is a person with a disability who has no limbs. Therefore, Robot helps him often. He has high self-esteem and says everything he wants to say. He also tends to step up and actively help his friends when they are doing something.

(Male) He has black hair and wears blue clothes with a red ribbon on his chest. He is in class 4-2 of a Korean elementary school. He has very high self-esteem and is so eloquent that he only picks the right words to say even when arguing. He is also incredibly smart.

(Male) He has bowl-cut hair and uniquely shaped eyes. He is in class 4-3 of a Korean elementary school. He is also an Ilbe user and always adds '-no' to the end of his sentences. (Example: Hello-no!) When flustered, he says "Igi." He has an extremely loud personality and thinks strange thoughts. He eats while making 'heobeo-heobeo' sounds.