Before his appearance in the books and films, Sauron was once a lieutenant to a greater Dark Lord, Melkor, renamed Morgoth, who was ultimately destroyed in the First Age, ending his rule in the North. Sauron, however, hid in the shadows unseen and discovered Mordor, to which he took advantage of its natural surroundings and chose it as his realm. He began to summon an army of Orcs through gruesome breeding and made alliances with the Easterlings, the Variags, the Corsairs of Umbar and the Haradrim.
During the Second Age, Sauron was seen as a threat, for he wanted to conquer all of Middle Earth so he could rule all life in it. So he forged the One Ring, using it to corrupt the other ring bearers, despite the Elves had hidden their rings and the Dwarves' rings were destroyed. The only people he managed to corrupt were the nine kings of men who wore rings, and they became the Ringwraiths. Because his previous plan failed, he gathered his dark forces and slowly began to conquer Middle-earth. But a Last Alliance of Elves and Men lead by Isildur, Elendil and Elrond attacked on the slopes of Mordor and slowly began to win the battle. But Sauron saw its victory and knew he had no choice but to fight them himself. He came out from the Dark Tower and killed many of the soldiers in the battle. He then attacked Elendil, killing him. His son, Isildur, picked up his father's broken sword, Narsil, and cuts off Sauron's finger with the One Ring on it. Sauron explodes and he loses his physical form. Isildur took the Ring, and Elrond told him to destroy it, but he refused. Later he was killed by Sauron's Orcs, to which he lost the ring in the Anduin river for 2,461 years.
The ring is later found by Deagol while fishing. Smeagol was with him and, since it was his birthday, he demanded the ring. When Deagol refused, Smeagol strangled him to death. The ring corrupted and deformed Smeagol, transforming him into Gollum, named after the horrible swallowing noise he made with his throat. In The Hobbit, he becomes the sorcerer, the Necromancer of Dol Guldur, and resummons the Ringwraiths, but the White Council and the Elves drove him out.
During the Lord of the Rings (near the late Third Age), he returns to Mordor, where he declares himself alive and rebuilds his massive army. He adopts the Eye of Sauron, a lidless and enflamed pupil, as his official insignia, which terrifies the people of Middle-earth. However, Bilbo Baggins's nephew, Frodo, gets the ring and takes it into Mount Doom, to which he throws in after a struggle with Gollum, thus destroying Sauron forever.
Sauron was sent by Lord Vortech to take over the city of Metropolis alongside Two-Face, retrieving the Locate Keystone and morphing Metropolis into a Mordor-like state, complete with his army of orcs and the Tower of Barad-dur. Batman, Wyldstyle, and Gandalf arrived on the scene not soon after, taking down Sauron's dark army and Two-Face as they approached the Tower. They eventually reached Sauron himself, who had the keystone perched on his throne. After the dark lord monologued, Gandalf noted how it seemed Sauron now served another, to which Sauron vehemently denied. Angered by their interference, Sauron used the power of the keystone to summon a Dalek ship, with several Daleks emerging from within and causing objects from other realities like Gandalf's fireworks cart and Batman's bat-signal to arrive from various portals. Eventually, the trio defeated Sauron, as his power was not as absolute as it was in Middle-earth, causing Barad-dur and the rest of his creations to collapse and for Sauron himself to suddenly compress into a cube before being sent back to Vortech's lair.
Sauron is one of the villains that joined Enoch's army. He assisted Galactus, Smaug and Darth Vader in acquiring the Ultimate Nullifier from the Marvel Comics World. He was one of the three that are defeated except for Galactus.
- Sauron returns to his giant form like it appeared in the LEGO Lord of the Rings video game.
- Some say he is a Foundation Entity because he created the One Ring, but he never existed before the very beginning of the Multiverse.
- Though his physical minifigure was never made, his Necromancer form is playable.
- He is almost similar to Ganondorf from The Legend of Zelda franchise.