Darth Vader

"What is thy bidding, my master?"

- Vader awaiting orders from Emperor Palpatine

"You have controlled your fear. Now, release your anger! Only your hatred can destroy me!"

- Vader tries to goad Luke to the Dark Side

"Luke, you do not yet realize your importance. You have only begun to discover your power. Join me, and I will complete your training! With our combined strength, we can end this destructive conflict and bring order to the galaxy!"

- Vader attempting to convince Luke to join him

Darth Vader (born Anakin Skywalker) is a powerful Sith Lord and an infamous villain from the Star Wars Saga. He is the central antagonist of the Star Wars Original Trilogy, and the main protagonist of the Prequel Trilogy. He stands as one of the most iconic villains in both Star Wars and fiction in general.

He was portrayed by David Prowse and voiced by James Earl Jones. In the prequel trilogy, Anakin Skywalker, Vader's previous identity, was portrayed by Hayden Christensen.

Childhood
The home planet of young Anakin Skywalker (Darth Vader) is Tatooine, a remote desert planet controlled by the Hutts. Anakin and his mother are poor slaves owned by Watto, a Toydarian junk dealer.

During the battle between the Galactic Republic and the Trade Federation, a Naboo cruiser's hyperdrive had been damaged, and it is forced to land on the planet. Jedi Master Qui-Gon Jinn searches for a replacement, and finds the nine-year old boy. He sensed that the Force was very strong with Anakin, and sent a blood sample to his apprentice Obi-Wan Kenobi. The result came back as a reading higher than Yoda's midi-chlorian count. This suggested that Skywalker was the one who could bring balance to the Force.

Since Qui-Gon did not have credits that were worth anything in Tatooine, he placed a bet with Watto in an attempt to win the needed hyperdrive, involving the pod race which Anakin was going to participate in. Before the race, Qui-Gon gave the boy advice about using his instincts, and to feel, not think. Anakin won, and he made the Jedi proud, as well as his mother, Shmi.

As soon as Qui-Gon acquired the needed parts for his ship, and as soon as Anakin brought home the winnings, the boy was freed. His new destiny was to become a Jedi. It was very difficult for him to leave his mother, and he knew there was much ahead of him.

Jedi Training
Anakin was once a Jedi, but he turned to the dark side in the third episode of Star Wars. When he became one of the Sith, he was named Darth Vader by his master Darth Sidious. Anakin's transformation into Darth Vader became complete when Sidious told him, "It seems in your anger, you killed her (Padmé)." The devastating anger and despair that Vader went through, after he discovered the painful truth, forever bound him to the dark side of the Force, or so it seemed.

Turn
Since Skywalker was a young Padawan he had been trained in the ways of the Jedi. But as he grew stronger and more powerful, he wanted more, yet he knew it was wrong. Anakin cared for the one thing too much in his life - Padmé. When he saw in a dream that Padmé was going to die, he swore that he would do everything he could to save her. He talked to Yoda and told him of his feelings of loss and pain. If the Jedi Council knew he had a wife which was strictly forbidden by the Jedi code, then he would be expelled from the Jedi Order.

Refuge
Anakin found security and refuge in talking to Palpatine. Palpatine had been like a father to him and had made him a member of the Jedi Council. But while talking to his dear friend one day, Palpatine revealed to Anakin that he knew the ways of the dark side of the Force, and it was clear that he was indeed the Sith Lord. Anakin was nearly brought to kill him on the spot, but Anakin realized that the evil chancellor was the only person who might be able to help him save Padmé.

The Choice
Shortly after Obi-Wan Kenobi had dealt with General Grievous on Utapau, Anakin delivered the message to the Chancellor. Palpatine began to talk calmly with Anakin, about how he was being excluded from the Council, and that they did not trust him. It was then that Palpatine revealed the truth about himself--he was the Dark Lord of the Sith. Anakin pulled out his lightsaber to kill him, but he knew that since he was a Sith, he had the power to save his wife. In despair, he told Jedi Master Mace Windu about the news. In great shock, Mace needed to move quickly to make sure the Jedi Order survived. Ordering Skywalker to stay at the Jedi Temple, he took various members of the Jedi Council, including Kit Fisto, to arrest the Chancellor. Anakin stared at the building which contained Palpatine's office, and his thoughts and emotions took control of his decisions. Anakin heard the Sith Lord's voice in his head: "If the Jedi destroy me, any chance of saving her will be lost." Anakin could not lose Padmé the way he lost his mother. He hurried as fast as he could to the Chancellor's Suite.

After going to the palace of Palpatine the young Jedi found the Sith Lord on the ground, with Mace Windu's lightsaber blade pointed at his chest. Mace told Anakin the only way to bring peace was to destroy the Sith Lord. But Anakin said it should not be done; it was not the Jedi way. Anakin had to make the choice. Jedi or Sith. As soon as the purple laser started its way to kill the Sith, Anakin's blue blade cut off Mace's hand. A smiling Darth Sidious yelled with power and cast Windu out the window with devastating Sith lightning. After helping the Sith Lord, the former Jedi Anakin Skywalker was no more. Darth Vader had taken his place.

Prequel trilogy
The prequel explains how Darth Vader came to be. Vader was once Anakin Skywalker, noted Jedi Knight who, tempted by Palpatine/Darth Sidious through the Dark Side of the Force, became the Dark Lord of the Sith. Obi-Wan Kenobi, upon learning what Anakin had become, engaged in a lightsaber duel with his former friend and Padawan learner on the lava planet Mustafar, ending in severe injuries that resulted in his being encased in black armor and mask that sustained him for almost the rest of his life.

Original trilogy
In the original Star Wars trilogy, Darth Vader is  a dark, ruthless figure set out to torture, or kill the films' heroes to prevent them from thwarting the Empire. He is one of the two main antagonists of A New Hope (the other being Grand Moff Tarkin), the main antagonist of The Empire Strikes Back, and the secondary antagonist of Return of the Jedi.

Battling the Rebellion and his son
In A New Hope, Vader is charged with recovering the stolen plans of the Death Star and finding the Rebel Alliance's secret base. He captures and "interrogates" Princess Leia and, along with Death Star commander Grand Moff Tarkin, destroys her home world of Alderaan. Shortly afterward, he duels his former master, the Jedi Master Obi-Wan Kenobi, who has arrived at the Death Star to rescue Leia, and cuts him down, turning him into a spirit in the Force. He then encounters his son, Luke, during the Battle of Yavin, and senses in him a great strength in the Force; this is confirmed moments later when the boy destroys the battle station. He was about to shoot Luke down using his TIE-Fighter, but Han Solo disabled his ship using the guns on the Millennium Falcon, and sent Vader spinning into space.

In The Empire Strikes Back, Vader captures Leia, Han Solo, Chewbacca, and C-3PO on the planet Bespin to lure Luke into a confrontation. He strikes a deal with the administrator of Cloud City, Lando Calrissian to give Han over to the bounty hunter Boba Fett, and has Solo frozen in carbonite. Luke, who has been partially trained by Yoda, duels Vader, but is eventually defeated, losing his right hand to Vader's lightsaber. Vader then reveals his true identity as Luke's father and offers Luke the chance to overthrow Palpatine and rule the galaxy as father and son. (Note that Vader never says the now famous line, "Luke, I am your father" but rather, "No, I am your father".) Luke refuses, throwing himself down a mine shaft. He is sucked into a garbage chute and rescued by Leia, C-3PO, Chewbacca and Lando. He is fitted with a robotic hand to replace the one Vader had cut off.

Redemption
"You already... have, Luke. You were right. You were right about me. Tell your sister... you were right."

- Anakin's last words

In Return of the Jedi, Vader is charged with overseeing the completion of the second Death Star. He meets with Palpatine on board the half-constructed station to plan Luke's turn to the dark side. By this time, Luke has nearly completed his Jedi training, and has learned from a dying Yoda that Vader is indeed his father. He learns about his father's past from Obi-Wan's spirit, and also learns that Leia is his sister. On a mission to the forest moon of Endor, he surrenders to Imperial troops and is brought to Vader. Aboard the Death Star, Luke resists the Emperor's appeals to his anger and fear for his friends, but snaps when Vader telepathically probes his mind, learns of Leia's existence, and threatens to turn her instead. Enraged, Luke nearly kills Vader, severing his father's right hand. He controls his anger at the last minute, however, as he looks at Vader's cybernetic hand and then at his own; he realizes that he is perilously close to suffering his father's fate. As the Emperor approaches, encouraging Luke to kill Vader and take his place, Luke throws down his lightsaber, refusing to perform the final blow. Angered, the Emperor attacks Luke with Force lightning. Luke writhes in agony under the Emperor's lightning, begging his father for help. Unable to bear the sight of his son in pain, Vader spiritually ceases to exist and the Anakin Skywalker persona returns. Anakin turns on his master and throws him into the very core of the Star, where the evil emperor was engulfed and killed.

Moments from death, he begs his son to take off his breath-mask so he could look at Luke "with [his] own eyes". Luke complies and for the first (and as it turned out, the only) time, father and son truly see each other. In his dying breaths, Anakin Skywalker is redeemed, finally admitting to Luke that the good within him was not destroyed after all. Luke escapes with his father's body as the Death Star explodes, destroyed by the Rebel Alliance.

That night, Luke burns his father's Sith armor in the manner of a Jedi's funeral. During the victory celebration on the forest moon of Endor, Luke sees the redeemed spirit of Anakin Skywalker, standing once again with Obi-Wan and Yoda.

Trivia

 * "Vader" is Dutch for "Father", foreshadowing the reveal of his true relationship with Luke.
 * Darth Vader's line "No, I am your father!" has become a well known memorable quotes ever in Star Wars, receiving many various parodies in many media, fanfiction or mechandise alike. One of the best & most memorable one would be in Toy Story 2 where Emperor Zurg that he is Buzz's father.
 * Also, many parodies of Darth Vader appeared in many various media such as Dark Laser & Darth Stewie.
 * Darth Vader also made a guest appearance in Night at the Museum 2: Battle of the Smithsonian alongside with Oscar the Grouch as one of the fictional figures who wanted to join Kahmunrah's army, only to be refused due to that the latter cannot understand Vader's breathing, thinking it as his language. Angered, he slams the lid of Oscar's trash can & is never seen again in the rest of the movie.
 * Darth Vader, alongside with Galen Marek & Master Yoda made a guest appearance in Soul Calibur IV as playable characters. In the game, Darth Vader was seeking on both the power of the Soul Edge & Soul Calibur where in his ending, he successfully found what he is looking for after he finishes off Algol & took both weapons with him, bringing the Empire to a whole new level of fear. Unfortunately, it received many criticism where many Star Wars fans complained about having Star Wars characters in the Soul Calibur universe being in the game & stated that they "didn't quite fit".
 * Each villain in the Star Wars prequels foreshadows a different aspect of what Anakin will become:
 * Darth Maul -The merciless apprentice who enforces Sidious's will as well as surviving a mortal wound from Obi-Wan and becoming a cyborg.
 * Count Dooku -The Jedi turned to the Dark Side
 * General Grievous -The wheezing Jedi-hunting Cyborg