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[1] during the quest Touching the Sky
Gelebor offers to help you get Auriel's Bow if you help him kill his brother, Vyrthur
