Herne the Hunter
Antler-headed leader of the Wild Hunt of Great Windsor Park. He existed long in folklore before Shakespeare used his legend (to Falstaff's distress) in The Merry Wives of Windsor.
As leader of the Wild Hunt, Herne is identifiable with Odin, Gwyn ap Nudd, Finn mac Cumhail, King Arthur, Bran, and the Headless Horseman.
More importantly, his name (Herne) and appearance (antler-headed) have logically lead to the conclusion that he is a half-remembered version of Cernunnos, Lord of Animals in Celtic Mythology, similar to the Hindu Pasupati, a manifestation of Shiva.