Sith Empire

The Sith Empire is a restored state ruled over by the Order of the Sith Lords. It controls a massive area in the Outer Rim in the North Eastern quadrant of the Galaxy, and is arguably the largest state in the Galaxy. It's capital world is Ziost, though the location of the Sith'ari at any time is unknown.

History
The Sith Empire considers itself the continuation of the Order of the Sith Lords, established thousands of years ago. The current Sith doctrine is that of the One Sith, established by Darth Krayt around 300 years before the current year.

Sith-Imperial War
The Sith ruled the entire Galaxy for a short while during this period, but they were overthrown by the combined might of the Jedi, Galactic Alliance, and the Fel Empire. Their leader, Darth Krayt, was killed during a battle on Coruscant and the remaining Sith fled into hiding.

Hiding in Plain Sight
Under the leadership of Darth Nihil, the Sith took up the strategy of infiltrating various organizations and emerging governmental bodies around the Galaxy. This allowed them to sway the direction of politics in their favor, driving faction against faction while they built strength.

New Leadership
Darth Geminus would become the new leader of the Sith sometime in the last 40 years. His background as the son of a Moff in the Draco Empire allowed him to gain a tremendous amount of resources while under the nose of the Empire. He created a plan that caused the Yavin Alliance to break into civil war while also destabilizing the Draco Empire. He would eventually be defeated through the combined strength of a Jedi and one of his own students.

During his time as the leader of the Sith, Geminus instituted a number of reforms. Firstly, the title of Sith'ari would be bestowed on the highest leader of the Sith Order. Second, he would choose a group of students to teach that would be part of an organization called "The Hand of the Sith". They were all potential successors, taught the most powerful of Sith techniques, and allowed to operate with near impunity. They could bow out of the Hand at any time and become a "Lord of the Sith", become allowed to take their own students but to be cast down in the rankings of potential successor to the Sith'ari. They would then be allowed to create their own operations that would further some branch of Sith teachings.

These changes to the Sith Order allowed it to grow far more than it had at any point since the death of Palpatine. Sith started becoming public again in certain places, like the Xervonic Hegemony. They would sell their services as mercenaries and advisors to regimes opposed to the philosophy of the Jedi order.

Geminus defeat left a divided Sith Order, however. His legacy would be far worse, as he'd organized the creation of the Sith Army before his demise.

Raath and the Rise of the Empire
Darth Wrath (known as Raath before) was a Pureblood Sith Warrior who helped defeat Darth Geminus. He assumed the Mantle of Sith'ari, but not without contest. There were a great number of Lords of the Sith who viewed his take over as a tremendous betrayal and they sought to overthrow him.

Through some cunning maneuvers, Wrath was able to organize the Jedi to take out his opposition, many of whom had gone over to the Xervonic Hegemony. He instigated a rebellion on Saleucami and pressured Xervo to deal with that threat. With him attacking and the Core Republic wanting to aid the Rebels after their own ambassador was set up in an assassination plot, war between these two polities was assured.

Xervo would be taken off-line (though whether or not he's actually dead is another question) by a group of Heroes tied up with the Saleucami Resistance. This left Xervo's forces in disarray for a time, making the Republic complacent before Wrath's master stroke.

The Sith Army, until this point hidden beyond the edge of the Galaxy, arrived at Tion and captured the shipyards there before the Republic's fleet could intervene. They managed to capture hundreds of starships intended for the war against the Core, as well as deploying their own newly designed ships as well. Combining this with a non-aggression pact with the Hutts gave Wrath all the confidence he needed to attack.

Before the Republic could respond, the newly comprised Sith Fleet smashed the Core Republic's Fifth Fleet and sent the survivors running for the Core. Shortly thereafter, the Sith arrived in Draco space and attacked. Wrath had successfully seduced a few major moffs to abandon the Draco Empire and side with him. Their betrayal sealed the end of the Sith-Draco war, and legitimized the Sith holdings in the outer rim.

The Core Republic sued for peace shortly thereafter, dealing now with a major refugee crisis as billions of sentients began to move from Sith Space toward the perceived safety of the Core. No longer able to deal with the Outer Rim militarily, the Sith managed to gain their own Empire in the course of a few weeks. Opposition Sith forces were destroyed or scattered. This begins the modern era.

Demographics
The total population of the Sith Empire is unknown at this point. Various wars and pogroms have destabilized the populace, causing refugee migrations over the last century.

Some species homeworlds are controlled by the Sith, including those of the Ruurians, Mirialans, Thalassians, Quarren, Mon Calamari, Felucians, Zygerrians, and many others. The Sith Lords themselves constitute members of species from all over the Galaxy, the only prerequisites for joining being Force Sensitivity and not following Jedi teachings.

Government
The Sith Empire is a theocratic imperial monarchy ruled by the Sith'ari (sometimes called the Sith Emperor). He is aided by the Hand of the Sith, constituting his five most prized students. Various other Lords of the Sith administer to the structure of the empire in a similar manner to Moffs.

The current Sith'ari is Darth Wrath, a Pureblood Sith who was preserved in carbonite for millenia before being thawed out and assuming control of the Sith. While not necessarily the creator of the foundations of the Sith Empire (those rightfully belong to Darth Geminus), Wrath was able to implement the plan and create something that rivals the Sith Empires of old.