Zabathag was a warden in the dungeons of Barad-Dur during the third age. he never left Mordor when Gondor came and gathered surviving orcs and uruks to fight the men of Gondor who controlled Mordor for the last 3 ages. he started to raise an army in the land of Nurn with the help of the Easterlings. When Lord Khamir came out of Rhun, Zabathag helped him reclaim Mordor and begin an assault on middle earth again.