Kōme Ogi is a fifth-grade student in Class 2 at Shiromidai Elementary School. She is a popular online illustrator who works under the handle Mumu. Her interest in the music of Kyō Nukui led her to create image art inspired by his songs. Due to an unusual upbringing, she can be strikingly out of step with ordinary society. Her primary ability is her skill as an illustrator, which she uses to contribute artwork related to the music she admires. In the story, she appears as a supporting character, connected to the main cast through her online presence and artistic contributions. Her development is closely tied to her engagement with the music and the people around it, though specific details about her personality, deeper motivations, and key relationships are limited.