Gelebor is an NPC in Skyrim: Dawnguard
He is a Snow Elf.
He is the keeper of the Great Chantry of Auri-El.
He oversees the Wayshrines there
You find him in Darkfall Cave during the quest Touching the Sky
Gelebor offers to help you get Auriel's Bow if you help him kill his brother, Vyrthur