Black Uruks

The elite black uruks of Barad-dur were the greatest orcs Sauron ever had.They were originally uruk-hai of Mordor that fought at Dagorlad that survived and that ransacked and killed Isildur.During the Third age,they were given the   title of 'Great Black Uruks of Barad-dur' and were 10,000 strong and guarded the Dark Tower with all their strength.At the Battle of the Black Gate most of them were killed because Lugburz crumbled,some fled to the Misty Mountains.