Kael'thas Sunstrider

Prince Kael'thas Sunstrider was the son of Anasterian Sunstrider and the leader of the Sin'dorei during the Third War. The Sin'dorei became split between those on Azeroth and those who followed Kael'thas, under Illidan's Forces. He aimed only towards helping his people during the aftermath of the Scourge's destruction of Quel'thalas. After following the failed New Alliance that was led by Garithos, Kael'thas led his people to follow Illidan into Outland. Though Illidan promised a "cure" to the magical addiction of the Sin'dorei, Kael'thas grew impatient with Illidan's promises, and forged an alliance with Kil'jaeden to use the blessed Sunwell to summon the Man'ari into Azeroth. Kael'thas was defeated once in the Tempest Keep, and finally killed in the Magisters' Terrace by the Shattered Sun Offensive.