Speak with Brother Anton in Desolace.
My brother in arms, Brother Anton, heard rumors of an undead infestation in distant Kalimdor, in a land known as Desolace. Anton immediately booked passage to that place, to seek and destroy the undead menace!
He is looking for those with the bravery and resolve to aid him. If your heart is true, then speak with Anton. He is in Desolace, in the Alliance town of Nijel's Point.