Fordred Aran

Fordred Aran was an archmage who Arthas killed when he raided Dalaran. His ghost was later put to rest by Kael'thas and Vashj when they escaped from the Dungeons of Dalaran.

Trivia

 * His name was taken from a random archmage found in Warcraft III: Reign of Chaos.
 * Aran is the word for king in a number of languages constructed by J. R. R. Tolkien.

Speculation
Judging from his surname, he might be a relative of Nielas Aran and Medivh.