Ebony Maw researched the Pym Particles and figured out the way for Nebula to jump to the alternate timeline, so she could bring Thanos' forces to the future.
In 2023, Nebula and the other Avengers time travel via the Quantum Realm to an alternate 2014. Nebula goes with Clint Barton, Romanoff, and Rhodes to the planet Morag. After Barton and Romanoff leave, Nebula and Rhodes render an alternate version of Quill unconscious and take the Power Stone from the Temple Vault.
Ostensibly he went into the past to return the Infinity Stones the Avengers had “borrowed” in order to reverse Thanos's finger snap. But it also gave him a chance to be with Peggy Carter, the love of his life.
And though you might expect 2023 Nebula to start bleeding out or disappear, she's completely fine. That's because when 2014 Nebula traveled to the future on Thanos' orders, she created a split timeline.
Avengers: Endgame: Timeline Paradox Explained | How Nebula Does THAT To Herself | Dimension Theory
What happened to the nebulas body?
The shot fired by Drax the Destroyer caused Nebula's entire body to be damaged, but her cybernetic implants helped to repair her within moments, twisting her arm and jaw back into place, although she winced in pain as the organic parts of her arm still hurt.
Although made from vibranium, Bucky's arm doesn't have any special abilities or hidden tricks, whereas Nebula's new arm (assumed to have been created for her by Rocket) is composed of nanotechnology.
Thanos never cared much for Nebula, even going so far as to say in Guardians of the Galaxy that Gamora was his favorite. That could be because, to Thanos, Nebula was nothing more than a means to spare Gamora while still obtaining the Soul Stone.
Nebula never knew that the cost of the soul stone was to lose whom you love most. All she knew was that Thanos went to Vormiir with Gamora and she wasn't with him when he left.
Vision is killed by Thanos when he removes the Mind Stone to complete the Infinity Gauntlet in order to initiate the Blip. Years later, Vision's body is reactivated via Wanda's magic, albeit initially without his memories and with a different appearance.
Bucky owes his youthful appearance to repeated cryo-freezes orchestrated by the Russians. He possesses no super powers and never received a form of the Super Soldier Serum as many assume, but continues to operate at peak human ability.
How Can Captain America Lift Thor's Hammer? Simple: Steve Rogers is worthy. The inscription on Mjolnir reads “Whosoever holds this hammer, if they be worthy, shall possess the power of Thor.” It doesn't matter how strong you are, if you aren't worthy, you can't lift Thor's hammer, no matter how hard you try.
Peggy and future Steve would have taken great care to keep his true identity a secret. And it is because he needed to keep this secret that future Steve did not tell Sam Wilson (Anthony Mackie) the truth about his wife when Sam questioned him about his wedding ring at the end of Endgame.
A Galactic Antagonist. As a youth, Nebula grew up in a torturous environment created by Thanos. Having the Mad Titan as a parental figure would have been bad enough, but she was also constantly compared to her surrogate sister Gamora. Thanos openly favored Gamora, which drove Nebula mad with jealous rage.
Throughout the MCU films we see that Nebula as a cyborg can take huge amounts of damage and can self repair itself. We see her tanking attacks from a super powered Adam Warlock and even Yondu's arrow. Yet in Endgame her 2014 self gets killed by present day Nebula with a single laser blast.
In the movie "Captain America: The Winter Soldier," it is revealed that Peggy Carter has children and Steve Rogers is their father. The writers of "Avengers: Endgame" confirmed that Steve is the father of Peggy's children and that they likely have super soldier DNA.
Killing her past self only kills past-Nebula because, for past-Nebula, her own present is a layer impacted by her own death. Good-Nebula's own present, a layer of time stretching across infinity, continues uninterrupted.
While Gamora saw her little sister as more of an incompetent annoyance, Nebula saw her big sister as a true threat. Because of this, Gamora and Nebula never actually united against Thanos within Marvel Comics' panels. However, the two eventually did make peace and parted amicably.
When Gamora finally does confront Thanos, she believes for a moment that she's killed him and breaks down, crying. An orange light passes over her--but it's fleeting. Whatever love Gamora has for Thanos is all but smothered by darkness.
As proven by Thanos sacrificing Gamora, he's a being capable of love. While he may not have had affection for Nebula in her adult years, her growth and ability to fight with 100 percent of herself every time were enough for him to pay attention to her and try and "help" her to ensure she never lost again.
Nebula's feelings on the death of Thanos are understandable, especially with the way Gillan broke it down in her quote. Despite his abusive nature, the Mad Titan was the only parent figure that the character has had for a long time.
In the 2022 Guardians of the Galaxy Holiday Special, each member of the team gets a personalized gift. Rocket, following his tradition of collecting metal body parts, is unexpectedly given Bucky's arm. More impressively, it's actually the newer black and gold vibranium arm that Bucky got from Wakanda.
After the titanium arm was destroyed by Iron Man in 2016, he was given a vibranium arm by T'Challa during the Infinity War of 2018. The vibranium arm was later taken from Barnes by Nebula, who gifted it to Rocket Raccoon as a Christmas present.
