During the events of Alien: Covenant, the audience learns that David created the xenomorphs by experimenting with the Engineers' deadly "black goo" pathogens, as well as the reproductive organs of Elizabeth Shaw (Noomi Rapace).
According to “Advent”, David killed Shaw after she refused to help David “build a second Eden,” and used her body in his research to create (or recreate depending on your preferred theories) his incarnation of the Xenomorph. “I tried so desperately to make her more than human.
In the novelization of Alien: Covenant (which was based on the script) it says the engineers created the Xenomorph. In the Covenant DVD commentary, director Ridley Scott says David created the Xenos.
Therefore, the character's treacherous actions in the films, such as infecting the archaeologist Charlie Holloway with an alien mutagen, would be from a desire to create a new evolutionary generation of his own.
It's never actually stated what species Alien: Covenant's Engineers, a.k.a. "Space Jockeys," actually are, as David kills them all with the black goo in a very brief scene.
ALIEN COVENANT: DAVID'S EXPERIMENTS ON ELIZABETH SHAW
What happened to Shaw after Prometheus?
Sometime after the events of Prometheus, Shaw was killed by David. She was seen on a table dissected, being experimented on. David claims she died in the crash of the Engineer ship.
The crew of the USCSS Prometheus believed that the abandoned planet they explored was an outpost for weapons engineering and development, lending credence to the theory that the Engineers created the Xenomorphs (or perhaps more specifically, the Black Liquid that led to the Trilobite) for war and genocidal purposes.
Why did the Engineer drink the black liquid in Prometheus?
The opening shot of Prometheus features an unforgettable sequence wherein an Engineer named Sacrifice drinks the black goo - which was later discovered by the android, David, on LV-223 - from an urn to create humanity itself, which is accomplished through an act of literal disintegration.
Eventually, Shaw was able to successfully reattach David's head to his body. The two were successfully able to locate the Engineer's homeworld before Shaw entered one of the ship's hypersleep chambers.
Alien: Covenant leaves this unresolved, but the fact David "killed" Walter previously by stabbing him in the neck, only for Walter to recover from the blow, suggests Walter has a more advanced design than David, which includes healing injuries quickly.
What Was David's Mission in Prometheus? David's mission was to help Weyland learn not only the meaning of life, but also to help him extend his life by communicating with the Engineers. The reason he infected Holloway with the black goo was that he wanted to test it on a human to see if it was the key to immortality.
As Prometheus strongly suggested that the Engineers created humans thousands of years ago, the question of did the Engineers also create the Predators have often come up in the fanbase. However, it is clear from the Predator lore that the Engineers did not create the Yautja.
The Alien Egg appeared in 2017's Alien Covenant. These were David's creations and not exactly the same eggs that we've seen before. They didn't come from a Queen Alien but from David genetically engineering them and therefore look a little different.
So it was revealed near the end of Covenant that Shaw actually didn't die in a ship accident as according to David, but instead was used as a host for one of his earliest experimentations with the alien life form.
They land on a mysterious planet to investigate only to find that David has killed Shaw in order to use her DNA to develop more aliens and create his own special species. He's also killed all the Engineers for unclear reasons, perhaps also in hopes of creating more aliens.
The Trilobite was a massive, octopus-like creature resulting from Charlie Holloway being infected with Chemical A0-3959X. 91 – 15 and engaging in sexual intercourse with Elizabeth Shaw. Similar to a Facehugger, its primary purpose appears to be to implant an embryonic Deacon into a host.
Whyte portrayed one of the "Engineer" aliens seen in Ridley Scott's 2012 science fiction film, Prometheus. He has portrayed various characters requiring a physically tall actor in the HBO series Game of Thrones, including White Walkers in season 1 and season 2 and a giant in the opening episode of season 3.
What was the alien doing at the beginning of Prometheus?
This creation is shown in the film's opening in which an Engineer sacrifices itself after consuming the dark liquid, acting as a "gardener in space" to bring life to a world. One of their expeditions creates humanity, who create artificial life (David) in their own image.
The greed and hubris that humanity displayed were perceived as an act of betrayal by the engineers, which is why they plan to destroy planet Earth, erase its inhabitants and start again.
"The line that David speaks to the Engineer (which is from a longer sequence that didn't make the final edit) is as follows: "/ida hmanəm aɪ kja namṛtuh zdɛ:taha/.../ghʷɪvah-pjorn-ɪttham sas da:tṛ kredah/" A serviceable translation into English is: "This man is here because he does not want to die.
The Xenomorph life cycle is thus: an egg hatches a small alien, often referred to as a "facehugger" (known scientifically as an ovipositor). This critter attaches itself to the face of a living being and implants an embryo inside the torso.
However, David annihilated the Engineers as a "gift" to Shaw. When she balked at his genocide, David began using her as a specimen in his genetic experimentation, attempting to make her "more than human"; despite his efforts at keeping her alive during this process, she eventually perished.
Thankfully, one Alien comic series indicates that David not only survived long after his final movie appearance... but that he became an android messiah.
