Nebula is a Luphomoid assassin and an adopted daughter of the intergalactic warlord, Thanos. She is also the adopted sister of Gamora. She served as the right-hand woman of Ronan the Accuser during his and Thanos' quest to retrieve the Orb.
Raised in the service of the interplanetary warlord, Thanos, Nebula trained to be a Galaxy-Class Killer under the tutelage of Ronan the Accuser. Nebula would often train alongside fellow Thanos devotees Gamora and Korath.
One training scenario on the arboreal world of Dervani saw Nebula and Gamora pitched against each other in a competition to retrieve a data ingot for Ronan. The girls sparred on the surface, leading to Gamora throwing Nebula off a cliff, severely injuring her and requiring multiple cybernetic replacements.
Upon reaching adulthood, Nebula and Gamora served Thanos under the command of Korath the Pursuer. On a mission to locate the Orb on the planet Praxius IX, inside of one of the Cloud Tombs of Praxius, Nebula went in without waiting for Gamora and fell into a trap. Ensnared by an impenetrable Laser Thorn Energy Net, Nebula found herself at the mercy of the inhabitants and needed to be rescued by Gamora.
Never one to tolerate failure, Thanos ordered Gamora to leave Nebula behind, with only a sharp blade to free herself. Nebula was forced to amputate her own arm in order to escape the netting.
Thanos lent Nebula and Gamora to the Kree warmonger Ronan the Accuser, who made a deal to retrieve the Orb for Thanos so he would in turn destroy Xandar. When Korath the Pursuer reported that he had failed to retrieve the Orb on Morag, thanks to Star-Lord's intervention, Nebula was tasked to retrieve the Orb from Star-Lord. Nebula told him it would be an honour but Gamora insisted that she follow Quill as she knew Xandar. Ronan agreed and Gamora went on the mission.
When they left the meeting, Nebula confronted Gamora and they had a brief argument where they tried to break each other's fingers. Nebula accused her sister of attempting to become Ronan's favourite and they discussed who was the supiour killer. When Nebula mentioned that the screams of her victims could be heard across the galaxy, Gamora replied that it was because she took too long to kill them before leaving.
When Ronan and Nebula recieved word that Gamora had been planning on betraying Ronan and Thanos only to be sent to the Kyln with the Orb, The Other demanded they travel to the Sanctuary to discuss this with Thanos. There Nebula began repairing her cybernetic arm while Ronan argued with The Other, only for Ronan to kill Thanos' servant by snapping his neck. Thanos responded by threatening Ronan if he failed again which Nebula agreed with. As they left, Nebula assured Ronan that he would not win a fight with her father.
When they arrived at the Kyln, they discovered Gamora had already escaped with the Orb, with the help of Star-Lord and others. Ronan's soldiers took over the prison and Nebula tortured a Nova Guard to gather more information. She received a message on her cybernetics that the Nova Corps were on their way to defend the prison. As they were leaving Ronan ordered Nebula to send their Necrocraft across the galaxy to begin the search for Gamora and to cleanse the prison, murdering all of the guards and the prisoners.
- "You are a disappointment sister; out of all our siblings, I hated you the least."
- ―Nebula moments before attempting to kill Gamora
Nebula, Ronan, and Korath continued to search for the Orb, until they received a message from Drax the Destroyer telling them it was on Knowhere where they went to recover it. When they arrived they were spotted by Gamora and her new team, who escaped into a mining pod.
While Ronan began fighting with Drax, whose wife and daughter had been killed by the Kree, Nebula lead a squad of soldiers in fighters to chase Gamora across Knowhere until Gamora was forced to head into deep space which shut down her pod. Nebula destroyed her ship, despite her pleas, and leaving her for dead in space and retrieved the Orb.
Nebula and Korath were present when Ronan told Thanos he was aware of the Orb's nature as an Infinity Stone. Ronan ripped the Orb opened and harnessed its power, becoming the most powerful being in the universe. Ronan told Thanos he was going to destroy Xandar and then find and kill Thanos. Nebula offered her total loyalty to Ronan should he succeed as Thanos had tortured and mutilated her throughout her entire life. She swore to help him destroy a thousand planets. 
When they arrived on Xandar, a fleet of Ravagers lead by Yondu Udonta and Star-Lord engaged them. The fleet fired a blot of flame to disguise their moves, but Nebula saw that they had dived under the ship and she ordered all their fighters to destroy the ships. Once they received word that the side of the ship had been breached, Nebula tried to convince Ronan to retaliate but he refused, stating that his focus was to land on Xandar so that he could finally destroy it.
Deciding to take matters into her own hands, Nebula took a squad of soldiers with her to engage the attackers before shutting the door, locking in Ronan. When Star-Lord, Gamora, Rocket Raccoon and Drax breached the ship, Nebula confronted them. As Nebula began to insult her former sister she was silenced when Drax shot her with a rocket, sending her flying backwards and damaging her body.
Duel against Gamora
Nebula's body was damaged, but her cybernetic implants helped to repair her. Once she was repaired Nebula began to fight Gamora. During the fight the side of the ship was torn open, Nebula managed to gain the upper hand and began to electrocute Gamora until Gamora knocked her out of the hole in the Dark Aster and leaving Nebula hanging onto the edge of the hole.
As Nebula hung off the edge of the ship, hundreds of feet above the ground with her hand trapped on a spike, Gamora tried to save her and convince her to fight against Ronan, claiming that Ronan was crazy. But Nebula refused, citing that they were both crazy and instead attempted to commit suicide by cutting off her cybernetic hand. However, instead of falling from the sky to her death, she landed on top of a Ravager's M-ship. Nebula threw the pilot out and took control of the ship before flying it far away from the battle.
Like Gamora, Nebula despises her father, Thanos, for torturing her and turning her into a cybernetic assassin. However, despite this, she always tried, often in vain, to prove her worth to her father. Nebula resents Gamora for being Thanos' favorite daughter, which he has openly expressed even with Nebula present and she showed no hesitation in trying to kill Gamora more than once. Despite this Gamora doesn't not share these feelings for Nebula and even tried to convince her to betray Ronan and help the Guardians fight him even after trying to kill her twice.
Nebula has very little loyalty to a cause as she quickly betrayed Thanos once Ronan harnessed the power of the Orb, believing he could kill Thanos as he declared to do so. However when the battle of Xandar became too intense for her liking she quickly abandoned Ronan to escape, despite her sister's pleas for her to help the Guardians, possibly returning once again to Thanos. Unlike her sister who seeks to atone for her past crimes Nebula does not show any visible signs of regret for her own crimes as she was perfectly willing to murder anyone tasked to her and anyone who stood in her own way.
Ironically, despite her claims of hating her sister and her actions against her, it seems she does care for Gamora greatly. When Nebula destroyed the ship Gamora was in outside Knowhere, Nebula genuinely believed that she was doing Gamora a favor as she doubted that Thanos or Ronan would be so merciful as to give her a quick death.
Powers and Abilities
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- Luphomoid Physiology
- Superhuman Strength: Nebula has strength greater than that of a human being. She managed to throw a pilot of a M-ship out of the vehicle in mid-air.
- Superhuman Durability: Nebula can easily withstand multiple injuries. She managed to jump onto a M-ship from a great height without withstanding injuries.
- Superhuman Agility: Nebula has agility greater than that of a human being. She can easily keep up with Gamora in a fight.
- Cybernetic Enhancements
- Regenerative Healing Factor: Nebula's cybernetic implants allow her to quickly heal from otherwise near-fatal injuries, such as when her body was crushed and mangled when withstanding a direct blow from Drax's cannon. Thanks to her implants, she was able to reshape her body back to its original form by snapping her arms and jaw back into their normal place.
- Master Assassin: Ever since she was a child, Nebula has trained extensively as an assassin under Thanos and Ronan. She trained with Gamora throughout her childhood.
- Expert Combatant: An expert in armed and unarmed combat, Nebula was able to fight "the deadliest woman in the galaxy", Gamora, for a prolonged amount of time. She has been seen using retractable, baton-like electroshock weapons in battle which can be combined to form a longer electroshock staff.
- Expert Pilot: Nebula is an expert pilot, easily flying over a mining pod and an M-ship.
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In her early years under Thanos' wing, Nebula received various critical injuries that required her to endure extensive cybernetic augmentation.
- Contact Whiplash
- Tempersteel Claws
- Concussive Blasts
- Electroshock Weapons: Nebula's weapon(s) of choice are baton-like electroshock weapons which can be combined to form a longer electroshock staff.
- Thanos - Adoptive Father and Former Master
- Guardians of the Galaxy
- Head Riot Guard † - Victim
- Nebula's appearance in the movie seems to be based more on her second incarnation from the comics.
- Nebula shows complete loyalty to Thanos most of the time, but also states that she would gladly destroy a thousand worlds if it meant Thanos would die. This is possibly out of fear towards him, but may also be out of hatred, due to Thanos constantly undermining her in favor of Gamora.
- In Guardians of the Galaxy Prelude, Nebula loses her entire left arm and has it replaced by cybernetics; however, in Guardians of the Galaxy, her left hand appears to be made of flesh.