The leader of Genius 4 (known as G4 for short), a police investigation unit. She is a genius, bossy girl who looks down on Milky Holmes since they lost their toys, and is particularly annoyed by Sherlock (by calling her Kokoro-chan), often whacking her with a gold mask. She always says that she graduated in Harvard in the age 13 and that she has an IQ of 1300. Her name is based on Edogawa Rampo's Kogoro Akechi.