Cernunnos

Celtic God of the Underworld and Ruler of the Dead 

Cernunnous (the Horned One) is the ancient Celtic god of the underworld and ruler of the dead.  Images of the dark sorcerer etched into cave walls in France date back to 9000B.C.  He is portrayed as a horned deity surrounded by fearsome animals.  Also associated with hunting and fertility, Cernunnous became identified with the Antichrist when Christianity spread to the Celtic regions.  After the conversion of Ireland, Cernunnous was increasingly linked with a dark and foul underworld, the dwelling place of evil spirits and souls of the damned. (o)

Resource List - all entries are taken verbatim from the original source:

(o) "The Encyclopedia of Hell."  Miriam Van Scott.  St. Martin's Press.  ©1998