Yoshino was the leader of the bullies in the RPG horror game "Misao." She can be considered a minor/supporting character in the game, but she was a major player in Misao's disappearance and eventual death.
In the Misao novelization, her full name is revealed to be Kazuki Yoshino (吉野 一樹 Yoshino Kazuki) - (making Yoshino her surname).