Caranthir

Caranthir is a main character in The Witcher 3 who appears in 3 quests, including “Wandering in the Dark” and “The Battle of Kaer Morhen”. You can meet Caranthir in Velen/Novigrad as well as on Skellige.

From the journal

This Aen Elle elf was one of Eredin's advisors and also, on account of his extraordinary abilities, an important officer of the Wild Hunt. Calling on arcane magic Caranthir would guide the Riders of the Hunt along mystic pathways through time and space in order to reach other worlds.

He was also a master of more immediate forms of transport, such as the teleportation he made ample use of during the attack on Kaer Morhen.

Yet even with his tricks and spells Caranthir still died during the final battle against the Wild Hunt, his body swallowed up by the cold waters of the ocean.