Miku Moriyama is a high school girl who appears in the story as a capable and mysterious dungeon explorer. She has light pink hair that fades to cream at the tips and reaches her neck, with pink eyes. She is often seen smiling with a cat-like expression and enjoys wearing brightly colored clothing.

Her personality is friendly and cheerful, with an overall jovial demeanor that persists even in difficult situations. Despite her cheerful exterior, she possesses an elusive quality that adds to her intrigue. Miku is highly skilled at all kinds of games, a talent that translates directly into her abilities as an explorer. She fights alongside a small Carbuncle-like familiar named Snatch, which aids her in battles within the dungeons.

Originally, Miku was part of Airi Jinguji's exploration party, operating alongside Airi and Hikari Tanabe. After meeting the protagonist Kaito Takagi, she later joins his group, becoming a close ally. Her closest friend is Hikari Tanabe, and she also shares a strong bond with Airi and Kaito. During an exploration trip, Hikari collapsed, which moved Miku to tears, revealing a deeply caring side beneath her usually bright attitude.

Her motivations are not explicitly stated, but her exceptional gaming skills and natural aptitude for dungeon exploration suggest she is driven by enjoyment and a desire to test her abilities. She appears to value her friendships and supports her companions in both combat and emotional moments. Throughout the series, she demonstrates growth in her willingness to open up and rely on others, though she maintains her characteristic playful and mysterious nature. Her notable abilities include a mastery of various game-like skills and the effective use of her familiar Snatch in combat, making her a valuable member of any exploration team.