Dullahan

The headless horseman that prefigures death is the Dullahan. He carries the head beside him, with its horrible, beastly grin. 
The Dullahan clan came to North America from Ireland and quickly settled Boston, a territory they lost when the Reaper Matriarch refused to cede it to them during the First Organized Synod. Instead, they acquired wide swathes of the Midwest, including Chicago.