Another personality of Teach-kun, a narcissistic entity created by Teach-kun due to his own loneliness. Although he looks like a rabbit, he is actually a chimera born from a mixture of various emotions within the personality. His true form is a black monster called Nakami-kun, and when Samu becomes enraged, Nakami-kun bursts out from his mouth. After the main story, he usually appears in the form of a tail called Ichigo-chan. He loves Teach to an excessive degree. He harms himself when he gets overly excited because of Teach or when Teach fails to notice him. However, when Teach self-harms, Samu is also the one who treats the wounds. Since they share a body, the consequences are transmitted to Teach as well. Because Teach cannot directly perceive Samu's existence, Samu communicates with him through recordings or letters. As time passes, he shows a more mature side, ceasing self-harm and patiently learning how to write. Initially, his only social relationship was with Teach, the object of his obsession. He showed an exclusive and hostile attitude toward others approaching Teach, such as getting jealous when Brian hugged Teach and snapping at him not to touch Teach-kun in an angry voice. However, after Brian helped Samu by teaching him letters and helping him make Valentine's chocolates for Teach, they became quite close. Later, he even cried when Brian disappeared and became friendly with the people in the Gray Space, showing significant progress in his social relationships. He now seems happy that he can communicate with Teach anytime through writing even if Teach forgets him, suggesting his obsession has eased slightly. For some reason, he gained the ability to perceive Shu or travel to the Gray Space.

A character who shares a body with Teach, appearing as a black cat. In the beginning, he had a malicious personality, bullying Teach or destroying the radio cassette Samu prepared and the cushion gifted to Teach, but as time goes on, he shows affection and concern for Teach. He acts tough by flipping the bird or baring his teeth fiercely, but in reality, he has a fragile personality, crying over slander and libel, and suffers from Social Communication Disorder. He can shift his consciousness into Teach's body, at which point Teach's eyes turn into Kobayashi's emerald eyes. He breaks the fourth wall by craving attention through channel subscriptions, likes, and viewers, and uses polite speech toward the audience. His first-person pronoun at these times is 'Watakushi'. He likes wine, cheese, and cigars, but hates bamboo shoots. He supposedly likes Gorgonzola cheese in particular. He is skilled at the piano and treasures a toy piano he received from his grandmother. He considers himself handsome.