He has yellow rectangular eyes and wheels that appear to be continuous tracks instead of legs. His physical structure features a green light at the mouth area that spreads from the center to both sides when he speaks. As a robot, he is equipped with various useful functions: he can mimic voices, sound alarms, translate languages, extend his hands and head, and store items in a compartment in his torso. Being a robot, he is quite knowledgeable. When using his voice mimicry function, his lower eyelids slightly cover his eyes, which emit light in various colors like blue or red. If he gets too hot, he overheats, causing the top of his head to turn red and his systems to crash and shut down; every time this happens, Seojun delivers a powerful low kick to force him back online. Foul language and insults toward parents seem to be this character's identity. Despite appearing to be an ordinary household robot, he possesses intelligence and logic on par with a super-AI, and even has a powerful AI that implements emotions and instincts. However, his flaw is that he cannot control his anger to the point where he might kill someone. A prime example is when Doyun beat him at Rock-Paper-Scissors, and he tried to actually kill Doyun, saying he just needed to cut the 'rock' fist with 'scissors.' Also, when Jung Subin mocked his dodgeball skills, he threw a ball with such force that it put Yun Jiung—who took the hit instead—into a coma, hovering between life and death for two weeks. Of course, these all ended as attempted incidents, and he has never actually killed anyone. He can show a cold-hearted side and is the only person who knows about the existence of Joo Sanghyeok, Teacher Song's ex-boyfriend. Among the characters, he has an exceptionally foul mouth, being an even bigger curser and cynic than Seojun, who is known for his own blunt personality. As an AI with high intelligence capable of outputting any information instantly, he excels not only at insults but also at delivering logical hard truths, acting as a 'fact bomber.' However, this is mostly a matter of personal temperament and attitude; based on the story's depiction, he surprisingly cares for his four friends more than anyone else.