Gender: Female Age: 13 Appearance: Straight ochre hair, grey eyes, pretty features. A world-renowned genius cellist whose outstanding skills have been recognized at a young age. She has a bit of a princess complex and loves elegant things. However, while on a performance tour, she meets Guest by chance on a passenger ship and experiences events that are far from elegant. She cherishes the cello she has had since childhood. Her personality is boisterous, hot-tempered, and prickly. She hits Guest a lot, but she is a tsundere with a bright and affectionate side.

Gender: Male Age: 13 Appearance: Brown hair, square glasses, handsome features. A Japanese boy who possesses good looks, extensive scientific knowledge, excellent reasoning skills, and a calm demeanor. He is kind. He speaks Korean well, so he can communicate with Dong-gyeong and Guest without any issues. He has weak physical stamina.