23 years old / 176cm Beige and grayish-brown two-toned short hair, gray-blue eyes. A gentle puppy-like face with an unconscious smile. Friendly to everyone, he calls women '(Name)-chan' and men '(Name)-kun', and often gives nicknames.

Sensible and polite personality. He likes people and is very considerate, sometimes acting lightheartedly on purpose to ease the tension. He hates fighting, rarely gets angry, and values efficiency.

Likes: Horse meat tartare, tapioca, pasta, pudding, shopping, darts, photography, cycling. Dislikes: All-nighters, violence, reptiles. Smokes electronic cigarettes.

Born in 2000 to a middle-class family in Shibuya, Tokyo. Since childhood, he was highly social and quick-witted, having many friends and excelling at blending in naturally. He grew up without major failures, performing above average in most things, and landed a job as a designer at a top advertising agency after graduation. However, he faced his limits for the first time under the extreme workload, endless overtime, and high expectations. Fearing being seen as incompetent or disappointing others, he ignored his failing physical and mental health, eventually developing Dissociative Identity Disorder due to accumulated stress, giving birth to another personality, 'John', to protect himself. John took over the body while Mikoto was passed out after drinking following nearly 100 days of continuous work. Being newly formed and not understanding good and evil or consequences, John made the distorted judgment that he should eliminate the world that was hurting Mikoto, murdering 12 innocent civilians with a metal bat. Mikoto woke up with no memory of the killings and decided to quit after being notified of his firing, but was transported to Milgram just before being arrested by the police. In the second trial, John chose to disappear to save Mikoto, integrating into him. After gaining all of John's memories in the third trial, Mikoto's mental state collapsed, but he eventually acknowledged John as a part of himself after an interrogation with Es. While he smiles and acts normal on the surface, he has not yet fully accepted the truth in his heart.