This galaxy has always been mostly devoid of life, with only a handful of worlds developing simple bacterial life. Only one planet developed multicellular life, the planet of the Tsund. The Tsund are a now-extinct race which were the only self-aware life to emerge in the galaxy. They died out after 240000 years of existence due to a planet-wide nuclear war.
This galaxy does not have much in the way of resources, so no large empire ever really settled the galaxy. There were a few research station created by humans to study the Tsund, but these were later abandoned during The War for All.
In 125207, the Templars set up their nation Templaria in the galaxy. They were the first major civilization to ever inhabit the galaxy. The Templars had to deal with the lack of resources and infrastructure but eventually managed to fully colonize the entire galaxy.
By 130000, the population of Templaria rose to over 5 quintillion. Which made the Templars the most common humanoid robot model in the universe.
By 150000 the population rose to 20 Septillion. Nearly every planet was colonized by the Templarians, and several wormholes were built to connect the galaxy to Andromeda. The galaxy had better infrastructure than the average galaxy, with wormholes connected almost every star, Dyson swarms were around almost half the stars in the galaxy, and hundreds of thousands of factory worlds building drones, starfighters, and Templars.
During The War for All, the galaxy was invaded in what was known as The Battle of Templaria. This battle destroyed most of this fantastic infrastructure and ended the lives of the vast majority of the Templars. This set back the civilization of The Templars back almost 5000 years and made them start over almost entirely. To this day, Templaria remains a late-type II civilization when before the war they were Type III.
A vast majority of humans do not trust the Templarians, even after their contributions to the War for All. Therefore, The Templarians are mostly ignored by the Confederacy and are not allowed to leave the Galaxy. They were given complete autonomy and observer status on The Intergalactic Council.