The Headless Horseman

The Headless Horseman was a virtual representation of one of Ratonhnhaké:ton's genetic memories, relived by Desmond Miles in 2012 through the Animus.

Description
Daniel Boone told Connor about the Headless Horseman.

Dialogue
Connor looked for clues leading to the Headless Horseman. He found a victim's corpse, and spotted the Headless Horseman laughing as he rode away.
 * Boone: I've never seen him myself but I've heard the stories from here to Kentucky. A German mercenary - Hessians is what they call 'em - was fighting a battle when a cannonball took his head clean off. His whole battalion was routed and they lost the encounter. But the lad didn't die. He's been wandering the bush on horseback around the battlefield ever since, searching for his head, chasin' innocents when he sees 'em, taking their domes for his own. He wears a pumpkin for a head now, until he finds what he's looking for. Like I said, I haven't seen 'em, but I have seen the bodies he leaves lying about, headless and grotesque. God rest their souls.

Outcome
A new tale was unlocked in the Database.

Reference

 * Assassin's Creed III