Nebula (Marvel Cinematic Universe)

"Out of all our siblings, I hated you least."

- Nebula before her attempt to kill Gamora

Nebula is the secondary antagonist of the 2014 Marvel movie Guardians of the Galaxy. 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).

Biography
A blue skinned deadly assassin, like Gamora (Only she is green), is a loyal lieutenant in Ronan and Thano's employ. Her advanced skill and cybernetic enhancements make Nebula a valuable asset but a resentment to her sister may prove to be her Achilles heel.

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).

Attack on Knowhere
Sometime during Knowhere, 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.

War on Xandar
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.

Future
It has been confirmed that Nebula will return in Guardians of the Galaxy 2. Karen Gillian will reprise the role and there are many rumors that Nebula will be the main antagonist or will return again as the secondary antagonist in the sequel.

Trivia

 * Her landing on a ship and throwing the pilot out is baring similarities of how the T-1000 threw a pilot out of a helicopter in Terminator 2: Judgment Day.
 * After the first wars both ended is similar to when Starscream retreats in Transformers (2007).