The Ganguros are a trio of female high schoolers who seem to blame Anri Sonohara for their troubles and bully her on several occasions. They are sometimes seen with their boyfriends, including Hiroshi and Takeshi. They later become victims of the Slasher and are shown leading Haruna Niekawa's Saika Army in their battle with Shizuo Heiwajima. Their names were revealed in "Durarara no Subete."
They first appear bullying Anri with Hiroshi. Izaya steps in, smashes Youko's phone and shaves Hiroshi's head and they retreat.