I don't own Stargate nor Warhammer
Prologue
It has been years since the Asgards committed mass suicide to prevent their technology from falling into the wrong hands and gave their legacy to the Tau'ri and declared them as the fifth race. Years since the defeat of the Ori and removed them from the galaxy. The Wraith was near extinct and as a precaution, the planet of the Irratus bug was quarantined. The Tau'ri disclosed the truth to the public and while there are some protests and riots, people are more interested in space travel than to complain.
The Tau'ri Federation was established after a long debate by the world governments. Social and environmental problems was solved in the years that followed. The environment was restored to pre-industrial condition and other planets and moons within the Sol solar system was terraformed and colonized. Laws are established that prohibit the uplifting of primitive societies and the trade of technologies as they are '"too young" as the Nox would say. That said, people are reluctant to colonise planets that already have native sentient population even those with potential to have sentience most likely due to the history of colonisation centuries ago. Terraforming and construction of orbital colonies businesses as a result are booming.
The military was not neglected as defense was put in place and the home system was fortified to the teeth. Shipyards was built to make the ever growing Tau'ri fleets both military and commercial. Precaution was also put into place in order to prevent the emergence of space piracy.
Due to medical technologies and genetic engineering the average lifespan of the Tau'ri span centuries so far. Hereditary diseases are now all but a distant memory as most diseases. Average IQ and height is also increasing and scientist theorize that it is the natural evolution of and project that humanity will be close to the state of the Alterans.
Centuries later an experiment of the Ancient was discovered by the scientists. The findings made the Tau'ri wary as experiments of the Ancients or Alterans usually means big trouble and that is putting it mildly as it usually involve whole systems and even galaxy. Much worst since this particular experiment involve ascension. Such experiments is dangerous as it was done out of desperation therefore they expect no guidelines or laws about ethics or, morality even safety was followed.
They would have delayed tackling the problem but they have learned from the mistakes of the Ancients. The Wraith would not have been a problem if they have solved it earlier. Their hubris condemn humans to be livestock.
An expedition was prepared to investigate and to ensure that this experiment would not harm the Tau'ri or anyone for that matter. They prepare a self sustaining fleet as they expect to lose contact with earth for years even centuries. All the weapons derived in preparation for Ori level enemies who lives in the higher plane of reality was prepared and brought into the fleet. Human bodies has already been genetically enhanced to resist mind manipulation or any other Prior abilities. Although they have not tested it the fact that the ascended beings contacted the Tau'ri to sign a non-aggression treaty shows that at least they are nervous about it and they are headed to the right direction.
The ascended Alterans also gave details about the experiment as far as their non interference law would allow.
"It's the dimension where emotions, beliefs and feeling manifest . Where monsters and demon where given form by those who believed. Where gods were born if people believed long enough" Said the ascended envoy.
Every Tau'ri even those representatives of other powers were shocked at the same time want to smack the ascended envoy. It weren't for the non-aggression treaty that is already in place and the tradition of protection of envoys even during ancient savage times they would already have. There are things that should be left untouched until people are mature enough. The policy of not giving technology to those who are too young to understand also apply to them. They should not meddle in technologies they are not ready yet.
" An accident occur when two polar warp gates (the warp variation of a stargate ) each at both poles collapse and tear in reality was form unleashing the beings of immaterium ." The envoy continued
" Most of us died and the survivors either flees or use the experiment to make them into beings of the immaterium to contain Chaos , the term used to describe the malevolent forces within the warp. " The envoy stated. "After that all research about the warp was forbidden and the whole galaxy that contain the solar system of the planet Mallus was quarantined. The specifics of the forces of chaos are in data that I have given your scientists"
After that , preparation was continued using the clearly outdated data the ascended have given. Even when they ascended , they maintain the quarantine of the galaxy lest they attract Chaos attention. Unlike the one in Pegasus, there will be enough preparation as there is no immediate threat so far.
Weapons was formed based on the information given. The defense of the mind is given top priority as based on the information, it corrupt the mind then the body. Genetic improvement was researched to combat diseases and resistance to the warp. Soldiers was trained in scenario where the enemy vastly outnumber them. By this melee combat was not neglected as during these scenario , melee or close quarter combat is unavoidable. Close combat weapons and power armor was developed inspired by numerous sci fi games and series.
After long years of preparation, they are now ready.