Masumi Sera

Masumi Sera is a self-proclaimed high-school detective and practitioner of Jeet Kune Do. After making a mostly correct deduction during a murder case, with a hint that she made a mistake on purpose, she transfers to Ran's high school class. At Teitan High, she is also in Sonoko's class. She seems to know Conan is a detective and can fight at the same or better level as Ran.