Palps recounting Darth Plagueis's story to Anakin. Plagueis had attempted to glean the secret to eternal life. According to the theorist, Palpatine learned this secret from before killing his master. However, instead of cloning himself at first, Palpatine cloned Plagueis, resulting in Snoke.
He was created by the Sith Eternal on the lost Sith world of Exegol – several failed Snoke clone bodies can be spotted in a tank at the beginning of the movie. In effect, he was used as Palpatine's puppet; a way to restore order to what remained of the Empire and to help bend Kylo Ren to the Emperor's will.
The Star Wars universe establishes Snoke as a Force-sensitive artificial being created by Emperor Palpatine to reclaim control of the galaxy. As Palpatine's puppet ruler, Snoke leads the First Order against the New Republic and manipulates Luke Skywalker's nephew, Ben Solo, into becoming Kylo Ren.
Snoke Was a Strand-Cast Created by Palpatine
Although Snoke was bio-engineered in a lab on Exegol, he was a strand-cast, not a clone. This bit of Star Wars jargon means Snoke isn't an exact copy of anyone, but isn't natural-born either.
Since Snoke is a strand-cast, his height was likely deliberately determined before his creation by Palpatine and the Sith Eternal cultists. With this in mind, a tall and intimidating appearance is unsurprising for a being who was initially intended to simply house Palpatine's spirit.
When it comes to combat skills, there's no question that Palpatine was far more capable with a lightsaber in his hands than Snoke. Not many people can launch into a 920 corkscrew spin from a prone position and that includes the Supreme Leader.
When asked whether Snoke is more powerful than the infamous Sith Lords, Darth Vader and the Emperor, Andy Serkis responded, “Oh, without question. He has unlimited resources.” Although vague, this bold statement paints a picture of Snoke's potential power and influence as the Supreme Leader of the First Order.
In addition to rejecting Sidious, Dathan married a woman named Miramir, whom he fell in love with. Together, they conceived a child, their daughter Rey, who was born in 15 ABY. Although he renounced the Sith Eternal and his donor, the Palpatine bloodline would prosper through him, just as Sidious predicted.
Possibly unaware of his true nature, Snoke was an artificial genetic construct created on the planet Exegol by the Dark Lord of the Sith and Galactic Emperor Darth Sidious and his Sith Eternal cult during the reign of the Galactic Empire.
Darth Tenebrous was the Sith Master of Darth Plagueis.
As powerful as Darth Sidious may have been, it's easy to forget he actually seemed afraid of Master Yoda. As seen in Revenge of the Sith, Palpatine initially thought he could deal with the aged Jedi Master - and then, when Yoda proved able to counter the Sith Lord's Force lightning, he fled.
If not, the only logical explanation is that Jar-Jar is a member of the Sith. There are many theories surrounding the enigma that is Jar-Jar Binks. The most agreed upon theory, started by Reddit user Lumparoo in 2016, is that Jar-Jar is a powerful Force-user conspiring with Darth Sidious.
In The Rise of Skywalker (2019), the final film in the sequel trilogy, Palpatine is revealed to be the mastermind behind the First Order and creator of its puppet leader, Snoke, as well as the grandfather of protagonist Rey.
The son of Han Solo and Leia Organa, Ben Solo was seduced by the dark side of the Force and renamed himself Kylo Ren: leader of the Knights of Ren, champion of the First Order, and apprentice to Supreme Leader Snoke. Driven to destroy the past, Kylo killed his father and his master, supplanting Snoke as Supreme Leader.
The offspring of Darth Sidious' cloned son, Rey inherited her grandfather's power in the Force. Born on the planet Hyperkarn in 15 ABY, Rey was the daughter of a man named Dathan and woman named Miramir, but their names were later lost to history.
At the end of Star Wars: The Rise of Skywalker, Rey visited Luke's childhood home on Tatooine. While on the planet, when someone asked her who she was, Rey responded by saying that she was "Rey Skywalker." Although she wasn't related to them, both Luke and Leia had been mentors to Rey throughout the sequel trilogy.
Why didn't Snoke have yellow eyes? Because he wasn't a Sith, he was a strand-cast created by a Sith to corrupt young Jedi such as Ben Solo. Kylo Ren wasn't a Sith, he was a practitioner of the Dark Side, Snoke wasn't a Sith because he was a body used by Palpatine to be present elsewhere in the galaxy.
So in the comic it's stated that it was Luke who crippled Snoke. (Scar on top of head, part of his left face missing, having problem to walk properly and sit down).
While Snoke's mortality (assuming he's really dead) suggests that he isn't a Celestial, he could be related to them or have access knowledge derived from them.
One could theorize that he bore a child through some sort of space artificial insemination, or something closer to what we've seen in canon Star Wars material. In the canon comic Darth Vader No. 25, it is revealed that Palpatine somehow used the Force to manipulate midichlorions to impregnate Shmi Skywalker.
In The Rise of Skywalker's novelization, we learn that Rey's father was a failed clone of Emperor Palpatine. He was initially created to be a vessel to house Palpatine and his Sith power.
Despite being enemies, Rey and Kylo Ren share a connection called a 'Force dyad' and eventually become romantically involved with one another. Following Palpatine's final defeat and her own resurrection, Rey adopts the name Rey Skywalker to honor her mentors and their family legacy and renounce her lineage.
1 Darth Sidious
There has been no Sith, as powerful, meticulous, nor as evil as the Emperor himself, Darth Sidious. As previously mentioned, Sidious trained in the Dark Side by Darth Plagueis before Sidious killed Plagueis in his sleep, making Sidious a Sith Master.
Yoda is the grand Master of the Jedi Order and Supreme Leader Snoke is the wannabe Sith Lord who was chopped in half by his half trained apprentice. Yoda was a far superior swordsman and was also proficient in fighting the dark side, so there would be no way that Snoke could come close to even being a match for Yoda.
In Star Wars Legends and Canon, Galen Marek (Starkiller) is the only Jedi (other than Obi-Wan Kenobi) to put a beat down on Darth Vader/Anakin Skywalker. Galen was secretly trained as a Sith Lord apprentice to Vader, but returned to the light side and the Jedi.