The Star Wars universe seems to constantly be in a state of war, hence its name. As battles wage throughout the galaxy between Light and Dark, different factions arise to fight these wars, each with its creed and purpose.
Whether light or dark, strong or weak, each Star Wars faction has its advantages and disadvantages, both when it comes to in-universe strength and the love of the fans. As such, some of these contingents stand above the others as the very best in the Star Wars universe.
The New Republic
The New Republic is the government set up after the fall of the empire. Very little is seen of this group in the films, leaving audiences to piece together its characteristics from scattered tidbits of information strewn throughout the Star Wars universe. It appears as though this organization falls after Starkiller Base destroyed its capital planet of Hosnian Prime.
The New Republic has good intentions at heart, but it is far from the government that it was supposed to be. Naive and foolhardy, this organization failed to recognize the threat of the rising First Order, despite the desperate pleas from General Organa for their support. Ultimately, the government would fall unceremoniously, with its future uncertain after the eventual fall of the Final Order.
The Resistance
The Resistance is the special arm of the New Republic founded by General Leia Organa specifically to combat the rising forces of the First Order. Making its first appearance in The Force Awakens, this hearty group often finds itself strapped for supplies and manpower, fighting a war that always feels lost.
This fighting force is often far weaker than its enemies, though typically not of its failures, but those of the New Republic. While typically undersupplied and understaffed, the brave Resistance fighters make the most of what they have, though it is rarely enough to deal with the inexplicably well-funded First Order.
The Confederacy Of Independent Systems
The Confederacy of Independent Systems, sometimes called the Separatist Alliance, is a splinter-group from the Republic led by the fallen Jedi Count Dooku. After financing the creation of a droid army through the Trade Federation, the Separatists initiated the Clone Wars by capturing and holding hostage Senator Padmé Amidala and her two Jedi escorts on Geonosis.
Though the films portray the Separatists as maniacal and unscrupulous villains, certain episodes of the animated Clone Wars series make an effort to humanize those that sided with Count Dooku, making the CIS a more rounded alliance of planets and politicians. Ultimately, however, the fact remains that the Separatists had been manipulated by Dooku and his master, Sidious, all along, and they were eventually sacrificed like the pawns they always were.
The First Order
The First Order is the last remnant of the Empire, revived by the mysterious Dark Side wielder Snoke and his apprentice Kylo Ren. Intent on restoring an imperialistic rule over the galaxy, this organization wages war against the New Republic, transforming itself into the Final Order in Rise of Skywalker under the manipulation of Darth Sidious himself.
Despite not being backed by a government system as the Empire was, the First Order is a remarkably well-supplied, garnering a might that is comparable, even superior, to the Resistance. This fighting force easily asserts itself over the New Republic, replacing it as the ruling power of the galaxy.
The Rebel Alliance
The Rebel Alliance is the plucky confederacy of leaders unwilling to yield to the Empire's authoritarian rule over the galaxy. The group, which saw its beginning as early as the end of the Clone Wars through senators Amidala, Organa, and Mothma, finally grew into a fighting force capable of toppling their overlord and restoring peace to the galaxy.
The Rebellion has always been a favorite faction within the Star Wars fandom, with many fans calling for certain Rebel leaders to be given their own Clone Wars-style spinoff series in the Star Wars universe. These brave warriors were the first heroes introduced in Star Wars, and remain the lovable underdogs that every fan could root for.
Sith
The Sith, though only depicted in films as pairs of two, was once a large and powerful organization much like the Jedi Order. Ascribing to the Dark Side of the Force, this group wreaked havoc throughout the galaxy in their unending search for more power.
There remains remarkably little known about the Sith Order in canon, though many hope to see this group fleshed out more in future Star Wars series, such as The Acolyte. However, this group stood as a worthy adversary to their Light Side wielding foes, with its most prominent forging several important rivalries with certain Jedi.
The Galactic Republic
The Galactic Republic, as the audience meets it in The Phantom Menace, is a wide-ranging and powerful government that aims to keep a peaceful and united galaxy. Led by a Senate comprised of thousands of planets, the Republic is perhaps the largest alliance of planets to have ever existed.
The Republic, for all its bureaucratic failures, remains one of the most stable forms of government in Star Wars canon. Had it not been for the manipulations of its Supreme Chancellor, the Republic may have prospered long beyond the Clone Wars. This system was strong enough for Palpatine to convert into the Empire, however, keeping its governmental institutions for nearly two decades before disbanding the Senate and asserting his full rule over the galaxy.
Jedi
The Jedi Order is comprised of thousands of Force-wielders who have vowed to only tap into the Light Side of their power, swearing by an all-important Code. Powerful and brave, the Jedi aims to be peacekeepers, yet often find themselves dragged into the various conflicts of the galaxy.
Though the Order that is met in The Phantom Menace is a shell of what it once was, the Jedi remain fascinating, if an often misguided, group of religious zealots with a noble purpose. Many viewers of the franchise cannot help but become obsessed with this group, causing many fans to hope that certain Jedi are fleshed out better in their spinoff series.
The Empire
After the Great Jedi Purge, the Republic was transformed and restructured by Chancellor Palpatine into the first Galactic Empire, wherein he would be the Emperor. For two decades, the Empire ruled over the galaxy with an iron fist until its eventual fall at the end of Return of the Jedi.
The Empire is memorable for introducing several noteworthy villains that fans hope will return in future Star Wars content, such as Darth Vader, the Inquisitors, and Grand Moff Tarkin. More importantly, it asserted an iron grip over a formerly free galaxy. Using the institutions set up by the Republic of ages past, the Empire was one of the strongest governments that the galaxy had ever seen--and one of the most corrupt.
The Old Republic
The Old Republic is an earlier form of the Galactic Republic from thousands of years before the events of The Phantom Menace. In this age, the Republic functioned in line with the Jedi as it sought to expand its peace and prosperity to new corners of the galaxy.
Though much of what fans know about the Old Republic is no longer considered canon, the fundamentals of this era remain true: this was the Republic as it was always meant to be. This age precedes the days when political bickering and bureaucratic fallacies would stall the wheels of freedom, before the hypocrisy of the last generation of Jedi, and before the clouding of the Force that would allow a Sith Lord to rise to the most powerful position in the galaxy. This truly was the golden age of the Republic, reaching heights that no other faction would ever attain again.