Kaito's childhood friend, who always accompanies him when he goes to solve puzzles. She possesses great strengths, excelling at sports, and has a photographic memory, though she is not too good with actual puzzles. She often makes sweets that almost everyone finds delicious but Kaito is incredibly fearful of. After helping some kindergarten kids during a puzzle, she ends up with the title 'Nightingale'. This is a shock for her, since she sees everyone with a title as a "weirdo".