Where was your bravery? When we bled your wife, then gutted your son.
~ The Hamemr of Sauron to Talion.
The Hammer of Sauron is one of the secondary antagonists in the 2014 Lord of the Rings videogame Middle-Earth: Shadow of Mordor. He was once a stretcher-bearer for the Numenorean army during the Battle of the Last Alliance. However, after discovering Sauron's discarded mace, the stretcher-bearer took it for himself, and from there became one of Sauron's most dangerous and loyal servants.
He was once a stretcher bearer during the War of the Last Alliance, but he became disillusioned, and came across the mace of the Dark Lord Sauron. He was seduced by its power, and decided to give soldiers the glory that they wanted on the battlefield instead of helping those who were wounded.
After coming to throw in with Sauron, the Hammer became one of his three Dark Captains alongside the Black Hand and the Tower. Each of them represented a different aspect of their master's character, and in the case of the Hammer, he represented Sauron's martial prowess and warrior's ferocity and strength.
He was present when his leader the Black Hand murdered Talion in a ritual that bonded him to the Elven wraith Celebrimbor. This ritual also saw the violent killings of Talion's wife and son, an act that embittered him towards the Black Captains. Talion would get his revenge on all of them, and the Hammer would be the first to be targeted. Talion confronted him after wrecking havoc on Sauron's Uruk forces throughout Mordor.
Though a frustrated Hammer struck down Talion's Orc ally Ratbag for his incompetence in preventing Talion's actions, and taunted Talion regarding the deaths of his family, he was ultimately unable to defeat Talion in a duel, falling to Talion's blade and being the first of the Black Captains to die. Talion would succeeded in his goal to kill The Tower and The Black Hand, and would attempt to defeat Sauron by crafting a new ring.
So the local Warchiefs did NOTHING to prevent this sacrilege?!
~ The Hammer.
Now, bring me the head of this Gravewalker!
~ The Hammer to his orcs.
The ranger from the black gate...
~ The Hammer upon seeing Talion.
The Dark Lord will RULE!
~ The Hammer during the fight.
How does your vengeance taste, Talion? Is not the darkness sweet?
~ The Hammer's final words to Talion before his death.
Though he is said to use Sauron's mace, said mace does not look like the one used by Sauron in the game, or during the Battle of the Last Alliance. However, it can be assumed that this is because the mace changed it's form to suit the needs of it's wielder (as it is confirmed that Sauron's equipment morphs and shape shifts with him).
In Shadow of War mobile, he alongside the Black Captains are allies.