Sauron (/ˈsaʊərɒn/)[T 2] is the title character[a] and the main antagonist[1] of J. R. R. Tolkien's The Lord of the Rings, where he rules the land of Mordor.

Tolkien noted that the Ainur, the "angelic" powers of his constructed myth, "were capable of many degrees of error and failing", but by far the worst was "the absolute Satanic rebellion and evil of Morgoth and his satellite Sauron".

Commentators have compared Sauron to the title character of Bram Stoker's 1897 novel Dracula, and to Balor of the Evil Eye in Irish mythology.

Sauron is briefly seen in a humanoid form in Peter Jackson's film trilogy, which otherwise shows him as a disembodied, flaming Eye.

The Ainulindalë explains how the supreme being Eru began the creation with good,[T 3] immortal, angelic spirits, the Ainur.

[T 6] Sauron served Aulë, the smith of the Valar, acquiring much knowledge;[T 10][T 11] he was at first called Mairon (Quenya: "The Admirable") until he joined Melkor.

[T 16][b] Sauron directed the war against the Elves, conquering their fortress of Minas Tirith (not the later city in Gondor) on the isle of Tol Sirion.

Sauron, as a werewolf, battled Huan, who took him by the throat; he was defeated and left as a huge vampire bat.

Eärendil eventually sailed to Valinor, and the Valar moved against Morgoth in the War of Wrath; he was cast into the Outer Void beyond the world, but again Sauron escaped.

[T 5][T 14][T 20][T 6] To seduce the Elves into his service, Sauron assumed a fair appearance as Annatar, "Lord of Gifts"[T 13] and befriended Celebrimbor's Elven-smiths of Eregion.

Enraged, Sauron made war and overran Eregion, killed Celebrimbor, and seized the Seven and the Nine Rings of Power.

[T 21][T 4] With the One Ring, Sauron soon dominated the Númenóreans,[T 21] undermining Númenor's religion, and inciting the island to worship Melkor with human sacrifice.

He returned to Mordor, openly declared himself, rebuilt Barad-dûr, and bred armies of large orcs, Uruks.

The palantír of Orthanc fell into the hands of the Company; Aragorn, Isildur's descendant and heir to the throne of Gondor, used it to show himself to Sauron as if he held the Ring.

[2] She called it "a bold move, to leave the book's central evil so undefined – an edgeless darkness given shape only through the actions of its subordinates",[2] with the result that he becomes "truly unforgettable ... vaster, bolder and more terrifying through his absence than he could ever have been through his presence".

The mists surrounding Barad-dûr are briefly withdrawn, and: one moment only it stared out ... as from some great window immeasurably high there stabbed northward a flame of red, the flicker of a piercing Eye ...

Tolkien writes in The Silmarillion that "the Eye of Sauron the Terrible few could endure" even before his body was lost in the War of the Last Alliance.

[T 35] In the draft text of the climactic moments of The Lord of the Rings, "the Eye" stands for Sauron's very person, with emotions and thoughts:[T 40] The Dark Lord was suddenly aware of him [Frodo], the Eye piercing all shadows ... Its wrath blazed like a sudden flame and its fear was like a great black smoke, for it knew its deadly peril, the thread upon which hung its doom ... [I]ts thought was now bent with all its overwhelming force upon the Mountain..."[T 40]Christopher Tolkien comments: "The passage is notable in showing the degree to which my father had come to identify the Eye of Barad-dûr with the mind and will of Sauron, so that he could speak of 'its wrath, its fear, its thought'.

"[T 40] Since the earliest versions of the Silmarillion legendarium, as detailed in the History of Middle-earth series, Sauron underwent many changes.

Called Tevildo, Tifil and Tiberth among other names, this character played the role later taken by Sauron in the earliest version of the story of Beren and Tinúviel in The Book of Lost Tales in 1917.

Gorthû, in the form Gorthaur, remained in The Silmarillion;[T 11] both Thû and Sauron name the character in the 1925 Lay of Leithian.

[T 43] The story of Beren and Lúthien also features the heroic hound Huan and involved the subtext of cats versus dogs in its earliest form.

[T 45] The classicist J. K. Newman comments that "Sauron's Greek name" makes him "the Lizard", from Ancient Greek σαῦρος (sauros) 'lizard or reptile', and that in turn places Frodo (whose quest destroys Sauron) as "a version of Praxiteles' Apollo Sauroktonos", Apollo the Lizard-killer.

In her view, both of these monstrous antagonists seek to destroy, are linked to powers of darkness, are parasitical on created life, and are undead.

He is briefly shown as a large humanoid figure clad in spiky black armour, portrayed by Sala Baker,[11][8] but appears only as the disembodied Eye throughout the rest of the storyline.

[20] He first appears disguised as the non-canonical human character Halbrand,[21] and then in the second season as Annatar (a canonical alias of Sauron), both played by Charlie Vickers.

[22] The Halbrand persona was conceived to make the audience share the feeling of being deceived by Sauron, and to ensure he would not overshadow other characters.

Afterwards, he would be allowed to function like other classic TV villains (such as Walter White or Tony Soprano), or Lucifer in John Milton's Paradise Lost.

He admitted he began to suspect when lines from John Milton's Paradise Lost, a narrative poem about the biblical story of the fall of man, were used during an audition.

[26] In the Marvel Comics Universe, the supervillain Sauron, an enemy of the X-Men created in 1969, names himself after the Tolkien character.