Nebula (Marvel Cinematic Universe)

"As a child my father would have Gamora and me battle one another in training. Every time my sister prevailed, my father would replace a piece of me with machinery, claiming he wanted me to be "her equal". But she won, again and again and again - never once refraining! So after I murder my sister, I will buy a warship with every conceivable machine of death. I will hunt my father like a dog and I will tear him apart slowly, piece by piece, until he knows some [...] of the profound and unceasing pain I know EVERY! SINGLE! DAY!"

- Nebula's motivation

Nebula is the secondary antagonist of the 2014 Marvel movie Guardians of the Galaxy, and an anti-hero in the sequel, Guardians of the Galaxy Vol. 2.

Nebula is an adopted daughter of Thanos, adoptive sister of Gamora (a Guardians of the Galaxy member), and one of two loyal enforcers of Ronan the Accuser (the other being Korath).

She is portrayed by Scottish actress Karen Gillian (who also played Amy Pond in Doctor Who).

Early life
Nebula is a Luphomoid assassin, and an adoptive daughter of Thanos, an alien overlord, taken in after Thanos slaughtered the rest of her kind. She was put under the tutelage of Thanos' henchman Ronan the Accuser to become a "Galaxy-Class Killer", and would connect with other Thanos minions like Gamora, a Zephoberei whose race was slaughtered by Thanos too, and Korath. Despite her loyalty to Thanos, Gamora was considered his "favorite daughter"; however, even though she was jealous of her, she apparently liked her to an extent, saying "of all our siblings, I hated you the least".

Thanos was obsessed with acquiring the Infinity Stones, objects of great power that he could use for his own purposes, later coming into possession of the Mind Stone and placing it in a spear that channeled its power. Gamora and Nebula were told that they were important to their father, but he was vague about what they could really do so as to avoid them using them to betray him.

In the prequel comic Guardians of the Galaxy Prelude, Nebula and Gamora sparred, and Nebula ended up falling down a cliff, forcing her to have most of her body fitted with cybernetic parts, making her a cyborg. In Guardians of the Galaxy Vol. 2, however, Nebula claims that Thanos regularly forced Gamora and Nebula to fight each other and every time Nebula lost, Thanos replaced a piece of her body with machinery in order to make the battle more equal. Later in the same comic, Thanos sent Gamora and Nebula to Praxius IX to get the Orb, which contained the Power Stone, but Nebula became trapped in a net. Thanos refused to let Gamora save her, and so Nebula was left with a sharp blade to free herself; she amputated her arm to do so.

Guardians of the Galaxy
Nebula first appears alongside Ronan, her former master. She witnessed the death of The Other, before her meeting with Thanos, her father. When Thanos wanted to obtain the Orb for unrevealed reasons, Ronan sent Gamora to retrieve the orb, but Peter Quill, a.k.a. Star-lord interferes with Gamora, both ending up in prison. Eventually, Gamora joined the Guardians, which left Nebula as Ronan's only enforcer (with the exception of Korath).

Sometime later, Drax, one of the Guardians, contacted Ronan while insane, which Ronan quickly came to Knowhere, searching of who made the call. When Ronan found out it was Drax, he dealt with him while Nebula was in search of the Orb. She made an attempt to kill Gamora, but Star-Lord saved her in time. Nebula was able to retrieve the Orb. They eventually learned that the Orb held an infinity stone, Ronan was going to give it to Thanos, but instead, he betrays Thanos by keeping it to himself, intending use it to destroy Xandar himself before destroying Thanos himself. Out of spite against Thanos for favoring Gamora, Nebula offers to help Ronan destroy a thousand planets in exchange for killing Thanos.

Nebula was still following orders from Ronan to destroy Xandar, which they were planning to destroy with Ronan's behemoth ship. The Guardians, with the help of the Nova Corps, eventually stormed through Ronan's ship and dealt with Korath, who was killed by Drax. Gamora was sent to open a door, but Nebula was sent to defend. Gamora and Nebula had a swordfight during when Ronan was trying to annihilate Xandar. Gamora got the winning hand and cornered Nebula to a cliff on Ronan's ship. Nebula let go and fell to her presumed death. Nebula, however, landed on one of the Ravager attack quads and tried to attack. She then escaped the war and left Ronan's side. She was never seen again in the film.

Guardians of the Galaxy Vol. 2
Before the event of the film, Nebula infiltrated the planet of the Souvereign and attempted to steal some of the Souvereign's energy batteries. However, she was captured and imprisoned by the Souvereign until the Guardians of the Galaxy arrived at the Souvereign planet and offered to help the Souvereign in battling an alien monster in exchange for Nebula. After the beast is killed, Ayesha keeps her word and delivers Nebula into Gamora's custody. On their way back to Xandar, where Nebula is to be imprisoned, their spaceship crashes. While most of the team travel on with their newfound ally, Ego, Rocket and Groot remain in the wreck to guard Nebula.

However, when the Ravagers turn up to capture the Guardians, Rocket runs off to meet them in battle. While he is gone, Nebula manages to convince Groot to free her so that she can help Rocket. However, once she had been freed she immediately betrays Groot. After Rocket has been captured by the Ravagers and Yondu refuses to assist in murdering the Guardians, a mutiny ensues. Nebula turns up just in time to witness the beginning of the mutiny and assists the mutineers by shooting the fin from Yondu's head with which he controls his telepathic arrow. She also blasts her gun at Rocket, electrocuting him.

Together with the Ravagers, now led by Taserface, Nebula sets off in their spaceship. However, after advising Taserface and his men to deliver the Guardians and Yondu to the Kree for maximal payment, she decides to set off on her own in order to kill Gamora and to track down and murder Thanos afterwards. One of the ravagers presents her with a spaceship and Nebula leaves the Ravager-base. In her spaceship, Nebula returns to Ego's planet. There, she spots Gamora siting alone in a field. She immediately heads her spaceship towards Gamora and starts firing. Gamora avoids being hit by jumping over a cliff but Nebula turns her ship around again and again, continuously shooting lasers at Gamora. Nebula even continues following Gamora when Gamora flees into a cave, causing the ship to crash as the cave is to narrow for its wings. This gives Gamora the oppurtunity to fire back, destroying the ship and trapping Nebula in the burning wreckage. Gamora pulls her sister out of the wreck seconds before it explodes.

Although both women are weakened, Nebula continues attacking Gamora until she eventually overpowers her and is able to draw a knife. However, she is unable to go through with murdering her sister and drops her. Nonetheless, she claims that she won and finally bested Gamora in combat, refering to the fights Thanos had them both fight when they were young. She spitefully confronts Gamora with the fact that Thanos forcefully turned her into a cyborg, ripping out her body-parts piece by piece only because Gamora was unwilling to let herself get defeated in their battles. She then claims that all she was wanted back then was a sister and that Gamora was all she had.

The two then try to get back to the surface, but while they walk they suddenly find a chamber deep inside the planet, filled with corpses and skeletons. They realize that Ego is up to no good and even Nebula joins the team in attempting to defeat them. While doing so, Nebula and Yondu manage to destroy the Souvereign fleet hunting the Guardians. During the final battle against the living planet, Nebula even saves Gamora's life.

Personality
Like Gamora, Nebula despised Thanos for his harsh treatment of her, but nonetheless, they both constantly strive for his approval. She became jealous of Gamora for being the one Thanos loved the most, but still liked her to an extent, hating her the least out of "all [their] siblings". Her hatred of Thanos was fueled over this, to the point that she sided with Ronan after retrieving the Orb; since he was now able to kill Thanos with the Orb's power, she decided that she would do whatever he wanted as long as her father was destroyed.

Gamora, however, didn't hate Nebula, and even tried to convince her to help stop Ronan from destroying Xandar; however, she chose not to, and amputated her own robot arm to escape the Dark Aster, escaping on a Ravager ship for parts unknown.

Allies

 * Ronan the Accuser † - Former Master
 * Korath the Pursuer †
 * The Other †
 * Guardians of the Galaxy - Former enemies-turned Allies and former teammates
 * Peter Quill/Star-Lord
 * Gamora - Adoptive Sister and former rival
 * Drax the Destroyer
 * Groot
 * Rocket Raccoon
 * Mantis
 * Yondu Udonta †
 * Kraglin Obfonteri

Enemies

 * Thanos - Adotpive Father and Former Master
 * Nova Corps
 * Head Riot Guard † - Victim
 * Ego † - Attempted Killer
 * Sovereign - Former Captors
 * Ayesha
 * Taserface's Ravagers - Former Partners
 * Taserface †
 * Gef †
 * Halfnut †
 * Wretch †
 * Brahl †
 * Scrote †
 * Narblik †

Trivia

 * Her landing on a ship and throwing the pilot out in Guardians of the Galaxy is baring similarities of how the T-1000 threw a pilot out of a helicopter in Terminator 2: Judgment Day.
 * After the first movie, she retreats from the Dark Aster, just as Starscream retreats in Transformers (2007).
 * In the original Marvel Comics, Nebula is a space pirate and mercenary. She at one point claimed that Thanos was her grandfather. During the Infinity Gauntlet story, she saw him use the Gauntlet's power to kill the cosmic entity Eternity and take his place; Nebula, furious at Thanos for turning her into a grotesque zombie-like creature, took the Gauntlet from him and restored herself to health, banishing Thanos from the universe so she could use the Gauntlet herself. Doctor Strange, however, assembled a team of heroes to defeat her, with Thanos himself as an aloof ally, tricking her into undoing everything Thanos did with the power the Gauntlet gave, and was imprisoned in a Titanian prison.
 * Nebula behaves similarly to Zuko from Avatar: The Last Airbender, both being the children of the primary antagonist before turning on the father and joining the protagonists.
 * In the Prelude comic to the first movie, Nebula's left arm is depicted as robotic, removing it with a blade to escape a trap; however, in the movie, it was seemingly-organic.
 * Prior to Karen Gillan taking the role of Nebula, Gal Gadot, who currently serves as Wonder Woman in the DC Extended Universe, was up for the role.