Confront Nathanos Blightcaller at Marris Stead in Eastern Plaguelands.
<The messenger appears visibly shaken.> Word has reached us of... well, I'm not quite sure how to put it... The Blightcaller has been found. Horde forces have been scouring Azeroth for any sign of him. Determined to make him answer for his crimes. One of our Argent patrols has found him. Not hiding in some distant land. Just... waiting at his old homestead. We have him surrounded, but, uh, I confess I don't like our odds. Perhaps you could gather your allies and bring him to justice.