Adon

Adon is a level 60 high elf NPC, located by the entrance to Quel'Thalas in the northernmost part of Eastern Plaguelands.

He doesn't fulfill any function and was only meant to be a sign that Quel'Thalas would be an 'add-on' (i.e. expansion) later found to be The Burning Crusade.

Trivia
His name is in reference to the term "add-on", as he was a sign that Quel'Thalas would be an "expansion" in the future.