Durarara!! SH, Vol. 3 (light novel)

A year and a half after the disbandment of the Dollars, the streets of Ikebukuro are
plagued by a series of assaults. And the person behind the attacks is...a character from
an anime set in Ikebukuro?! Meanwhile, Yahiro and company set out to stop the
Ikebukuro crime spree at the behest of Walker and Erika. And as the incident
escalates, the Headless Rider can't help but be reminded of the incident involving a
certain slasher...