Palpatine really was Star Wars' perfect Sith Lord. As committed as Emperor Palpatine may have been to the dark side, there's a curious sense in which he was a far from ideal Sith. There's actually evidence Palpatine became something of a Sith heretic, because he pursued attempts to combine technology with the Force that were considered heretical. He further seems to have played fast and lose with the Rule of Two, a mistake that ultimately meant he had no successor after his death in Star Wars: The Rise of Skywalker. Yet, despite all this, the truth is that he was singularly suited to the ways of the Jedi's sworn enemies.
In truth, the Rule of Two was always going to be unstable. It mandated that every Sith Lord should be concerned with their succession, but it is the nature of the dark side to become utterly self-absorbed and egotistical. Palpatine understood himself to be the living culmination of everything the Sith had worked for over the course of the last millennium. This is why doctrines like the Rule of Two mattered so little to him; he viewed himself as the Sith's end goal personified. The doctrines of the Sith thus became his tools, rather than his guides, to be dismissed almost at a whim.
Palpatine can be forgiven for his egotism, for he had something of a point. He was the one who achieved the revenge of the Sith, transforming the Republic into his personal Empire and wiping out the Jedi in Order 66. The importance of his position in the line of the Sith likely became clear to him early on his apprenticeship, for in many senses he was the perfect Sith Lord. Here are all the factors that made Palpatine the ultimate embodiment of the dark side.
Palpatine Was Born Into A Position Of Power & Influence
Little is known of Emperor Palpatine's backstory. What can be stated with confidence, though, is that he hailed from a wealthy and influential house on Naboo, one that potentially predated Naboo's joining the Republic centuries ago. He was therefore born a member of the aristocracy, wanting for nothing, with strong family connections in local politics - and probably beyond, if his family traded with other worlds at all. Many Sith would have to work to build power bases, but Palpatine was born into one, giving him a headstart on many would-be rivals.
Palpatine Was A Being Of Tremendous Dark Side Power
Palpatine claimed to be the most powerful Sith Lord of all time. It's difficult to quantify his claims, although his feats certainly support them; as seen in Charles Soule's The Rise of Kylo Ren comic, Palpatine used a Force Storm to destroy Luke's Jedi Temple. This act is singularly impressive, given complications with the Emperor's resurrection had left him stranded on the Sith redoubt of Exegol in the Unknown Regions, literally at the other side of the galaxy.
According to the old Expanded Universe, Palpatine's midi-chlorian count exceeded that of almost all Force-sensitives across the galaxy; he was exceeded only by the Skywalkers and Darth Vader's apprentice Starkiller. The EU was declared non-canon (or "Legends") after Disney acquired Lucasfilm in 2012, but most of the Force lore has followed through into the new Disney canon. Whether the midi-chlorian count is binding or not, though, the fact still remains that Palpatine possessed tremendous power. He also had a natural inclination towards the dark side, because by nature he was greedy and ambitious. The combination of his power and his character would have made him irresistible to his master, Darth Plagueis.
The Jedi Didn't Know Of Palpatine's Power
Taken aback when he discovered the young Anakin Skywalker on Tatooine, Jedi Master Qui-Gon Jinn famously stated the boy would have been discovered long ago had he been born in Republic space. He appears to have been alluding to some sort of midi-chlorian testing program conducted across some parts of Republic space, a program that would undoubtedly have stumbled upon the Chosen One. What is surprising, though is that Palpatine - a man whose midi-chlorian count would surely have been remarkably high - was not discovered by the Jedi.
This, more than almost anything else, made Palpatine supremely useful to the Sith. Palpatine learned to hide from Jedi senses, a skill that would allow him to act in their presence without detection. According to E.K. Johnston's novel Queen's Peril, Yoda was sensitive enough to detect a strange absence in the Force, described as a strange void in the Force. As the book states, "The light surrounded him, the dark a comfortable distance from the limits of his perception. And yet there was something; rather, there was nothing. And it eluded him completely." Yoda's mistake lay in failing to probe the cause of this absence, this nothing. His ability to sense the Force was diminished as the dark side ascended, and ultimately by the Clone Wars. Fear, violence, and hatred reduce any Jedi's awareness, cutting them off from the Force, and so Yoda ceased to become a threat. Once the Clone Wars began, Palpatine even used the dark side in the Temple, no longer afraid of discovery.
The Jedi Were Vulnerable In The Political Arena Where Palpatine Was Strong
The Sith had long known the Jedi were vulnerable in the political arena. The Jedi's lack of passion meant they struggled to understand the emotions and sentiments that typically drive politics; by the time of the prequel trilogy, they had grown so emotionally reserved they pursued justice without really caring about it. Palpatine was the only Sith who could use this vulnerability against the Jedi; once he had learned to conceal his presence in the Force, he could exploit his power base to launch a political career that would take him to the Senate.
Sheev Palpatine may have been the supreme egotist, but he was right to believe he was the only one who could achieve the revenge of the Sith. Tie-ins have suggested Darth Plagueis was the true mastermind, but Palpatine alone possessed the combination of political influence and raw power to fulfill the Sith scheme. He failed in the end, though, because the will of the Force brought the Chosen One into play against him and the Jedi returned. Palpatine may have ushered in the galaxy's deepest night, but the Star Wars saga proved that the light of the Jedi would extinguish every shadow cast by the dark side in the end.