At a glance, it is easy to dismiss humans as an unremarkable and unimportant civilization. They have very little in the way of biological or technological advantages. They're not the strongest, or the smartest, or the longest lived. They certainly don't have the fastest ships or the biggest guns. And then, there's the famous disposition.
It is said that the only time two humans will get along is when they have a third one to argue with. From the beginning of their recorded history, humans have fought each other. Over land, over resources, over beliefs. There hasn't been a moment since the founding of their civilization when humans weren't at war. If there's no cause for it, they will find one, and if their respective leaders won't go to war, the people will handle it amongst themselves. Paradoxically, their kind isn't particularly violent or mean tempered individually, but gather enough of them in one place, and you will see them devolve before your eyes.
As I said, it is easy to dismiss humans as unremarkable and unimportant. They seem quarrelsome, primitive, stubborn and self-sabotaging. Placed in ideal conditions, they will find a way to tear apart both themselves and everyone around them. But unlike any other species in the known universe, they thrive exclusively under adversity. If you were to take the most elite soldiers from any of the Galaxy's fiercest fleets, and put them under the right amount of stress and hardship, eventually, they would all crack under the pressure. Put a group of humans in the same situation, and you will see them become stronger, smarter, more resilient than you thought possible. Give humans whatever they ask for, solve all their problems, and they will just make more problems themselves. Give them an impossible problem to solve, on the other hand, and you will soon find out that the laws of physics are mere suggestions to them. The only time humans display their true, terrifying potential is when they're backed into a corner. It is due to this unique quirk that I believe that, in our greatest hour of need, they will be our strongest allies. It is also the reason why I think that they're potentially the greatest threat in the universe.
-From the classified reports of Prometheus, Imperial Emissary to Earth, 2154 AD
For 30,000 years, the Eternal Empire of the Othiri had watched over the younger races in its domain. Unbeknownst to them, the ever-vigilant Othiri had been protecting them from outside threats and, occasionally, from themselves. But as time passed and their influence dwindled, their leaders found it more and more difficult to protect their once heavily guarded borders. As the empire crumbled and their vast fleets withered away, these younger species, sheltered from the dangers of the universe, had to be brought into the fold. Like children lifted for the first time from their steel cradles and thrust into the wilderness, they came to know the world as it truly was: wondrous beyond their wildest dreams, yet filled with danger and death.
The first ones to be officially contacted were the Zargon, an inevitability at that point, given that they'd already managed to tame a sizeable slice of the galaxy by themselves, even without the aid of jump drives. Then came the Iridonian. Their civilization was ancient and advanced in many ways, yet their disinterest in space travel left them ill-prepared for what lay beyond their horizons. The Humans and Platharians were a risk, younger and more capricious than the rest. Contacting them was not an uneventful experience, but their natural aptitudes for space travel would have meant that they would get into trouble sooner or later, with or without intervention. The Tarlak were a surprise, a civilization they weren't even aware of. The Humans discovered them and became better ambassadors than the Imperial Remnant could ever have hoped. For nearly a century, this burgeoning galactic neighborhood was peaceful and prosperous, and the Othiri could rest easy, knowing that their legacy was in safe hands. Then came the Kharlath.
The narrative has been taken without authorization; if you see it on Amazon, report the incident.
When the first few sleeper ships arrived in Imperial space, around the 2230s, they were seen as little more than a curiosity. These large, scaly, reptilian looking creatures were not too dissimilar in appearance to the Humans or Zargon, yet their psyche was completely alien. Communication was difficult, and their aggressive tendencies were obvious, but despite their individual ferocity, they were deemed too few in number and technologically primitive to pose a threat. By the time the Mothership arrived, no one expected the Kharlath to be a threat. But their Mothership was unlike the rest, in both construction and complement. A vessel of unknown design and untold power, it brought with it hardened soldiers and vicious warlords, ready to wage war on anyone in their way. The real purpose of the sleeper ships soon became apparent: they weren't simple explorers but a scouting party, looking for planets ripe for the taking.
The Iridionians, who had welcomed some of the first wave of Kharlath with open arms, were the first to fall, slaughtered in their beds and bombarded from orbit. A coalition of Zargon and Platharian fleets managed to keep them at bay for a time, but their tactics were ineffective against the brutality of the assault. Every ship that wasn't completely destroyed was added to the Kharlath war fleet, every soldier left alive pressed into slavery. The Tarlak, pacifists to a fault, had no armies or warships to speak of, so it fell to the Humans to turn the tide. While the Coalition forces desperately fought to buy them time, the recently founded United Earth Commonwealth assembled the largest single fighting force that Human civilization had ever seen. A ragtag collection of cargo haulers, transport ships, and exploration vessels, outfitted with whatever weapons they could find, and crewed by hastily trained conscripts from around the galaxy. It was a far cry from the perfect fighting force, but it would soon become apparent that it was perfect for the job.
In 2247, the Humans achieved their first victory. The Kharlath Mothership, once seen as unbeatable, was damaged and forced to flee. For the first time in the war, the enemy had retreated. Over the following two years, a long and bloody war was fought for control of Imperial space. The Humans had managed to turn nearly every one of the Kharlath's tactics against them. Commonwealth ships always fought to the last man, and when all else failed, self-destructed rather than risk capture. Repurposed Kharlath boarding probes were turned against their creators. Although no match in single combat, the Humans boarded the enemy vessels and overwhelmed them with sheer numbers. Every victory came at a heavy cost, but the tide of war was slowly turning. But as the Kharlath were driven further and further away, it soon became clear that the war was far from over. As long as the Mothership stood, there was no hope for peace. As humanity faltered under the weight of the burden that had been placed upon them, they were charged with their most difficult task yet: they were going to steal the Mothership.