Mikado Sekimura is a member of the idol unit MooNs, which is part of the larger B-Project. Born on January 25, he stands at 177 centimeters tall and weighs 57 kilograms, with an average build. He has dark brown hair parted to the right side and green eyes, and his most distinctive feature is the glasses he rarely removes. He is consistently well-dressed, often seen in shirts and vests.

Mikado presents himself as a resourceful, intelligent, and capable young man. He is polite and gentlemanly in manner, and he manages to excel in his academic studies while also maintaining his idol activities. This dual dedication stems from his desire to prove himself to his father, who is a bureaucrat and holds strict expectations for him. However, beneath this composed exterior lies his true nature: he is a devoted otaku who loves the world of two-dimensional characters above all else. His particular obsession is the magical girl series Majokko Mamirin, but he goes to great lengths to hide this hobby from his colleagues and the public, keeping it a secret at work.

In the story, Mikado is a core member of MooNs, working alongside the other members of his unit as well as the wider B-Project group. His role involves balancing the demands of idol performances, promotional activities, and personal obligations. His relationships with his unit members are cooperative, though he tends to keep his private interests guarded. Over the course of the series, he occasionally lets his guard down around people he trusts, allowing glimpses of his genuine enthusiasm for anime and magical girls. This internal conflict between his polished public image and his private passions forms a key part of his character development.

His notable abilities include sharp intellectual skills, adaptability, and a strong sense of responsibility. He is able to compartmentalize his life effectively, maintaining high standards in both his academic and entertainment careers.