Tloinin Galaxy
The Tloinin Galaxy (often called "Incalescence" by those outside of the galaxy) is a Seyfert galaxy located roughly nine million light-years from the Milky Way. It largely empty of civilization, with only a handful of polities calling the galaxy home. A large portion of the galaxy is occupied by The Administrator and Delyatu, two artificial super-intelligences both qualifying as "Kardashev III" despite not technically being civilizations. The galaxy is the largest galaxy in the Tanta Group as well as numbering among some of the largest known galaxies.
There are several races native to the galaxy, the two most prominent being the Re'Tlel and the Vlanoans. These species are native to Tloinin and Onaud, respectively. These two worlds are by far the most populated planets in the galaxy, both having populations of over one quadrillion (including those residing in orbital habitats). Other more minor civilizations and worlds dot the galaxy, most of which choosing to ally themselves with either the Administrator or Delyatu, each one coming with a host of benefits and drawbacks.
As the largest galaxy in the region, Tloinin is a center for trade and political power for the Tanta Group. While the civilizations within the Tanta Group are used to the idea of the two powerful AI's within the galaxy, outside nations are wary of the idea of a single individual being so powerful. Nations such as the Confederacy of Borealis and Commonwealth of United Economic Nations, which have recently found out about the Administrator and Delyatu, have done little diplomacy with any Tantan nation.
History
The galaxy first came to be at about the same time as the Milky Way did, 13.5 billion years ago. For three billion years after it formed, the galaxy harbored no life as its stars had too low a metallicity to harbor anything more than icy asteroids. As time went on, planets bearing life began to form. This life would soon evolve intelligence, causing many civilizations to exist within the history of Tloinin. The oldest evidence of civilization in the galaxy dates back to three billion years ago.
More recently, as several other civilizations began to form, the galaxy began to truly harbor galactic-scale civilization. As early as three hundred thousand years ago, dozens of civilizations had influence on a galactic scale. There were even several Kardashev III civilizations in the galaxy's history. Just like every other galaxy, these nations rose and fell regularly. The Kal Federation became Kardashev III in 1299 BCE, making it the latest of these large civilizations (that arose with no outside assistance). After the formation of the Kal Federation, another polity emerged, called the Re'Tlel Equilibrium, a nation entirely controlled by The Administrator.
The Administrator had one purpose, to govern the Re'Tlel, with all other tasks pushed aside. At first, it simply slaughtered any and all sapient individuals that were not Re'Tlel. This strategy, however, proved foolish. The Kal Federation immediately intervened and very nearly destroyed the Equilibrium and the Administrator. Several hundred years afterwards, the Administrator re-emerged in another area of the galaxy having cloned more Re'Tlel for it to govern. Rather than seek vengeance, the Administrator had gained a sort of "humility" that made it view genocide as an unfavorable course of action. From there it continued to expand in secret.
Sometime later, in 18840, around the height of the power of the Kal Federation, Dreltvei came to be. Not much is known about this entity, as it almost immediately united with a hivemind nearby to where it came to be to form Delyatu. Rather than operating as a nation, Delyatu operated like a force of nature. It believed that it was created to right all injustice in the universe, and the only way to do so would be to make everyone exactly equal while also making them perfect. It converted every individual it came across into what are known as Vlanoans, semi-corporeal beings that were once naturally occuring sapient beings. These beings serve Delyatu in its crusade to bring justice to the entire universe, and do not hesitate to make use of their power when in service to their master.
The spreading of these two forces, one that wanted nothing more than to maintain the status quo and one that wanted to radically change the universe from the ground up would lead to disaster. In 31,009, the Tloinin War began. This conflict began as fears of Delyatu, an entity only encompassing a small star cluster, grew. The Kal Federation and a dozen other nations declared war on Delyatu. The Administrator would join them. The war, however, was simply too much for the mundane nations to handle, causing a collapse of most large civilizations at the time. All that was left in the galaxy was The Administrator and Delyatu, too opposing forces of equal might. In one of the longest wars in history, the Administrator and Delyatu leveled large swathes of the galaxy, killing large numbers of uninvolved combatants. By 35,000, both sides were damaged to the point of losing their status as "galactic powers."
The Administrator managed to begin diplomacy with the Confederacy of Borealis, a polity that had already sent large numbers of probes into the galaxy. It told them about the "strange anomalies" it was fighting and how "they could spread to other galaxies if left unchecked." They agreed to offer a fairly large number of ships in exchange for information about the anomalies as well as rights to several dwarf galaxies. The Confederacy had no idea they were creating diplomatic relations with an artificial intelligence. These ships allowed the Administrator to destroy the last of the Vlanoans and it just managed to force Delyatu into submission. In a treaty signed on Triyvaya, also called the "Planet of Corpses," The Administrator and Delyatu agreed to a peace of sorts in which they would stop all fighting in the galaxy. The Administrator also agreed to limit all injustice within the borders of the Equilibrium, an easy feat for the superintelligence. The galaxy was finally at peace in 36,038.
As time went on, both the Equilibrium and Delyatu expanded to control large portions of the galaxy. Their dominion over the galaxy, while by no means absolute, is quite substantial. Currently, they both qualify as superpowers. Recent strife, caused by what is known as The Exhumation, is likely to destroy this fragile peace, flinging the galaxy into what would likely be a far deadlier sequel to the original Tloinin War, likely involving foreign powers trying to put a stop to it.