Why and how did Sauron, the primary antagonist in Mordor.
While J. R. R. Tolkien did not prescribe to the idea of absolute evil, he stated that Sauron harbored an evil will that came as close to the idea as possible. Sauron has also been likened to Balor of the Evil Eye in Celtic mythology, who was a giant and the leader of a horde of malevolent supernatural beings known as the Fomorians. Sauron’s origins can be traced back to the beginning of time itself, as he was a Maia of Aulë named Mairon, a powerful spirit shouldered with establishing order in the newborn world. Although Sauron’s origins are angelic, he becomes captivated by the idea of ordering things as per his own will, which might be a possible reason behind him being lured by Morgoth, a Dark Lord who corrupted countless souls and waged wars against Elves and Men throughout the First Age.
Over time, Sauron rises up Morgoth’s demonic ranks, assuming the mantle of Gorthar the Cruel, second in command. It is interesting to note that Tolkien points out the innate difference between Morgoth and Sauron, which is that the former wishes to corrupt and subvert the earthly realms, but Sauron’s sole focus is to control and rule, without necessarily resorting to malevolence. His fall, just like that of those of Saruman, Gollum, men in general and essentially every corrupted character in Middle Earth history, is designed to explore the innate capacity for evil, even in those with the most innocuous or innocent drives.
Ultimately, Sauron's obsession for increased power spurred him to attempt conquering Middle Earth throughout the Second and Third Ages, which ultimately led to the creation of the One Ring in the fires of Mount Doom. Around S.A 1000, Sauron chose Mordor as his stronghold and built the Dark Tower or Barad-dûr, and used The One Ring to control the other ring bearers, but failed to corrupt the Elves. At this point, war was inevitable, which led to the events of the Last Alliance, as recounted by Elrond to illustrate the innate fallibility of men when it came to power and the lure of the ring.
After Isildur’s betrayal, Sauron returned to Middle Earth as the Necromancer, who is featured in The Return of The King, Sauron’s corporeal power in Middle Earth comes to an end, and he is permanently thrown into the Void, much like his former master Morgoth. As summed up in Tolkien’s The Silmarillion, Sauron “rose like a shadow of Morgoth and a ghost of his malice, and walked behind him on the same ruinous path down into the Void.”
Through the narrative arc of Sauron, one of the terrible evils that stalk Middle Earth, Tolkien exemplifies that even the most irable of souls, when lured by power and the hunger to control, are susceptible to corruption, and can transform into unspeakable symbols of tyranny. Sauron initially started out as a being whose greatest virtue was order and planning, as he abhorred chaos of any kind. This is ironic, as his ion for order is gradually consumed by his obsession for control, paving the way for chaos and destruction of the highest order. Due to the duality embedded within his nature, as present within all races in The Lord of The Rings, Sauron’s actions sprang forth from a place of ambition but were besmirched by the evil that lurked deep within his heart.