Miyuki Sone is the yandere for the player in Kimi to Kanojo to Kanojo no Koi.
Miyuki is Shinichi's classmate. She is part of the School Drama club. Shinichi has know her since when they were children, and says that they eventually grew apart. She seems to have a different personality based on who she is with, as seen when she talks to Aoi Mukou differently when she is in front of her classmates than when she is alone.