Helmet Head by Mike Baron

He was just a rumor to the rough and dangerous “one-percenters”—a monstrous motorcyclist dressed all in black who rode the back roads of Little Egypt cutting off the heads of other bikers with a samurai sword. But on one terrible stormy night, Deputy Pete Fagan discovers that Helmet Head is all too real—and consumed with a fury that won't be satisfied until his demonic sword drinks its fill.