The Black Hand would lead the Black Captains into sieging the Black Gate, and during the siege, decided to start a ritual to bring the spirit of Celebrimbor to him.
Despite the mystery of his past, he is the most loyal member of Sauron's army, and being the embodiment of his manipulation. The past of the Black Hand is left in mystery, with a few spreading rumors that he was once a king who swore loyalty to Sauron by killing blue wizards, or the Black Hand being a servant of the dark lord since Númenór' fall. In addition he has a limitless army of orcs under the command of innumerable war-chiefs and encourages them to battle not only enemies but themselves in bloody power struggles that continually shift the way Sauron's armies are structured. There is also a lesser aspect of Sauron known as The Hammer that acts as one of his underlings. The Black Hand of Sauron is served by an elite group of Uruks known as the Talons of the Black Hand, as well as another aspect of Sauron known as The Tower.
The Black Hand of Sauron is by far the most powerful and dreaded of all the enemies encountered in the game and is a direct nemesis of the protagonist, being responsible for the murder of his entire family (alongside countless other innocents).