A member of the six
Archmage Aethas Sunreaver is one of the members of The Six, the ruling council of the Kirin Tor. He is located in the Violet Citadel, standing next to Rhonin and Archmage Modera. Also the Horde district, Sunreaver's Sanctuary, is named after him. This refers to his high position in the Kirin Tor. It's likely that he is the one who succeeded Kael'thas as a blood elven member of the six.