An organization led by the most powerful human mages in the world. They founded the city of Dalaran as a place to study and teach the ways of magic.
However, some mages of the Kirin Tor delved too deeply into necromancy, demonology, and other warlock magics. One of the most powerful, Kel'Thuzad, left the Kirin Tor to open a rival school of necromancy: the Scholomance. There, he and his students created the Plague of Undeath, which ravaged Azeroth and led to the rise of the undead Scourge. Kel'Thuzad himself became a powerful Lich, and chief lieutenant to the Lich King.