Durarara!! Vol. 3 (manga)

Twisted passion accelerates disaster!!
After twenty years of searching, Celty, the headless Black Rider, has at last found her missing head—bobbing through the streets of Ikebukuro on someone else’s neck! Though Celty pursues, the girl escapes on the arm of Mikado Ryuugamine, taking refuge in his apartment. But with both the legendary Rider and Yagiri Pharmaceuticals bearing down on Ryuugamine in their pursuit of the scarred girl, how can he hope to save his own neck?!