Altruis the Sufferer wants you to slay Lothros at Illidari Point in Shadowmoon Valley.
I still have respect for Illidan. Without him I would not have found my path.
He is not who he once was, however. His soul has been corrupted by power, his mind has been twisted by defeat. He has become what I am sworn to destroy and his pet servants, the Illidari, are as much of an abomination as any demon of the Burning Legion.
His grasp on Outland is slipping yet his reach is still vast. Prove you're not with him by slaying his lieutenant Lothros at Illidari Point in Shadowmoon Valley.