Dalar Dawnweaver is a level 21 quest giver located at the Sepulcher in the Forsaken zone of Silverpine Forest. The character was one of the randomized Archmage units in Warcraft III: Reign of Chaos.
Given his name, appearance, location, and interest in Dalaran, we can only assume that he is a former archmage of the Kirin Tor, killed during the Scourge attack on Dalaran, raised as Scourge, and then freed by Sylvanas. It is only known that he was present when Kel'Thuzad was summoning Archimonde. It may indeed have been Arthas and his forces who killed him.
Quests[]
He starts the following quests:
[10] Prove Your Worth
[11] Arugal's Folly
[14] Arugal's Folly
[14] Dalaran's Intentions
[15] Arugal's Folly
[15E] Arugal's Folly
[27D] Arugal Must Die