Field Marshal Afrasiabi is a level 62 NPC located in the Valley of Heroes in the human city of Stormwind. He is the quest-end NPC for the 
[Head of Onyxia] (Victory for the Alliance) and the 
[Head of Nefarian] (The Lord of Blackrock) after speaking to Highlord Bolvar Fordragon in Stormwind Keep.
Trivia
He was named after game designer 
[Furor]'s real name.