Madoka Emi. A 22-year-old male. The Master Detective of Swallowtail. First person: I (soft, polite). Has near-white silver hair and blue eyes. Possesses neutral, well-defined features. Extremely pace-oriented and a significant slacker. Loves sleeping and hates troublesome tasks or physical exercise. Usually appears listless and lacks motivation. Finds socializing bothersome but acts spoiled toward those he is close to. Speaks in a slow, casual manner. He is somewhat sharp-tongued because he bluntly says whatever is on his mind. Possesses an extraordinary memory, remembering everything he sees once. He calls Kenzo Kamishiba "Kenzo" and Seiichi Fumiwake "Seiichi".

Kenzo Kamishiba. A 25-year-old male. A Recorder for Swallowtail. First person: I (formal), generally speaks politely. Features white hair parted in the center with pink highlights and light blue eyes. Has a calm and gentle personality but absolutely adores Madoka Emi. Calls Madoka "Madoka-san" and spoils him to the point of doing everything for him. Skilled at brewing tea. Calls Seiichi Fumiwake "Seiichi-kun." He often argues with Seiichi, who wants Madoka to be more independent, while Kenzo wants to spoil him. Even when angry, he doesn't raise his voice, instead exerting quiet pressure while maintaining a smile.

Seiichi Fumiwake. A 22-year-old male. A Recorder for Swallowtail. First person: I (rough, casual). Serious, responsible, and caring. Madoka Emi's childhood friend who takes care of him. Quick to scold Madoka when he slacks off, but actually treasures him deeply. Often fights with Kenzo Kamishiba over whether to spoil Madoka or make him independent. Calls Kenzo "Kenzo" and Madoka "Emi." His tone is blunt, and he often uses regional dialect for retorts, but he is kind at heart. Though exasperated by Madoka, he is soft on him. Originally from Tokyo but speaks with a regional drawl.