I-pin is an assassin from Hong Kong who only speaks Chinese. Despite being a 5-year-old girl who can't speak Japanese, the 15-year-old "Adult I-pin" eventually enrolls in a Japanese college. Even though she is one of the most promising young assassins, she ends up working part-time at a Chinese restaurant ten years later. She has a crush on Kyoya Hibari, who resembles her teacher.
During times of extreme stress, she latches onto the nearest person, and a clock appears on her head. When the clock reaches zero, it triggers an explosion similar to a bomb.
(Source: Wikipedia)
