Boss

Boss was a spirit who appeared early on in the anime adaptation.

Appearance
Boss appeared to be a bald muscular human-shaped ghost with a prominent cleft chin and a black moustache. In the anime he has parts of his motorcycle fused to his back.

History
Boss was the leader of a biker gang. They all died while riding through Honeido Tunnel when a rider at the front slipped on a banana peel and caused a crash.