A Balrog is one of the more powerful creatures in the service of Sauron. The dark equivalent of wizards, Balrogs are Maiar seduced and corrupted by Morgoth, the dark mentor of Sauron in the First Age into his service, creatures of shadow and flame, and later on, some came to take orders from him. They were exceedingly powerful, and were as destructive and deadly as dragons. The chiefest and greatest of their race was their leader, Gothmog, who was slain by the warrior Ecthelion. The best known, Durin's Bane (later slain by Gandalf during the events of The Lord of the Rings), was one of the few Balrogs to survive the destruction of its kind in the War of Wrath during the First Age, in which Morgoth was captured and most of the Balrogs were killed.
Shadow of WarEdit
The Balrog who appears in Middle-earth: Shadow of War is named Tar Goroth, a Balrog in the service of Sauron. He was awakened from the depts of the earth by the Uruk necromancer Zog to aid the Dark Lord. After he comes back to life, he proceeds to kill his saviors and goes on a rampage against the enemies of his new master. He is later defeated by Carnàn, with help from Celebrimbor and Talion.