The Sith Eternal is one of the many factions in LEGO Dimensions 2: The Rise of Enoch, from the Star Wars franchise.
The Sith Eternal was a secret Sith cult that followed the Sith religion, preserving it after the destruction of the final two Sith Lords, Galactic Emperor Darth Sidious and Darth Vader. As Sith cultists they revered the power of the dark side of the Force and venerated Sidious, who cheated death by preserving his spirit in a cloned body. The Sith Eternal strove to prevent their master from dying again, and resorted to the science of gene splicing in hopes of building a more suitable vessel for his dark essence. Their experiments led to the creation of various artificial genetic constructs, known as strandcasts, such as Supreme Leader Snoke as well as the Emperor's cloned son, who sired a natural-born Force-sensitive daughter called Rey. None of their endeavors succeeded in producing a viable host for Sidious' soul, however, and he was forced to rely on life support machinery in order to survive.
The Sith Eternal hid in the Unknown Regions, establishing their lair in the Sith Citadel of the lost world of Exegol, which was also Sidious' place of exile following his first demise and the fall of the Galactic Empire. While former Imperial officers built a movement that evolved into the First Order, the Sith Eternal constructed the Xyston-class Star Destroyers comprising the Final Order—the largest fleet in galactic history. Their new-generation Star Destroyers were outfitted with an axial superlaser cannon that was capable of obliterating an entire planet. In addition, the Sith Eternal raised a generation of children not only to embody the cult's values, but to serve as elite soldiers, officers and fleet technicians in their military. Although they were not strong with the Force, the new generation was just as devoted to the dark side as the one that preceded them, and believed that the galaxy was theirs to rule by cosmic right.
The Sith Eternal's plans came to fruition by the time of the First Order/Resistance War. After many years, their fleet and army were ready for deployment when Sidious announced his return across the galaxy. By then Snoke had fulfilled his purpose by dying at the hand of his apprentice, Kylo Ren, who, as Vader's grandson, was heir to the powerful Skywalker bloodline. Using Snoke as a proxy, the Sith Eternal had groomed Ren to lead their forces as heir to the new Sith Empire. However, Ren renounced their cause by returning to the light side of the Force as Ben Solo; after the Sith Eternal destroyed Kijimi the Resistance invaded Exegol to prevent the Final Order's launch. The cult was ultimately destroyed along with their forces and the Emperor in the Battle of Exegol, preventing their goal to establish the eternal reign of the reborn Sith Order.