The Adamantine Empire
Calus claims to have overseen a reign of glory. His Empire was an immense military power, but valued willpower, learning, gentility, and subtlety. Debate was as celebrated as warfare. Savage pit fights coexisted with precise marksmanship and refined martial arts. The Empire crafted technological marvels that allowed every need to be met and every life to be lived in comfort.
As the Cabal Empire expanded, it encountered countless alien races and absorbed them into itself: indoctrinating their species, collecting their technology, learning their knowledge, and merging with their culture. The number of species within the Cabal Empire "defied reckoning," and examples of the things they created, whether texts, tech, or super weapons, were archived in carefully maintained athenaeum worlds for study and potential future use.
What he wishes is not only to bring back that golden age but to improve on it, making it more egalitarian and cosmopolitan.
Species of the Adamantine Empire
The Cabal are a bipedal, hulking species that appear to be omnivorous, as evidenced by their many sharp, irregular teeth and their historic love of wine. They have wrinkled, leathery tan-grey skin, a tall skull, dark wide-set eyes with slit pupils, and a very high, inverted-V-shaped upper lip that exposes the Cabal's upper gums and fangs. They come from a warm, humid climate, so they have to be constantly hydrated within their suits. Therefore, while a resilient species, Cabal cannot survive in some environment without climate-controlled gel suits. Cabal have long lifespans, able to live well over a thousand years without any apparent infirmity.
Psions are a powerful race of clairvoyant, psionic beings who were conquered by the Cabal in the hopes of weaponizing their abilities. After building the future-predicting OXA Machine and using it against the Cabal in rebellion, the machine was destroyed and they were enslaved. They have only recently been emancipated, countless centuries later.
The Clipse were once a more peaceful technological race who had arisen on the moon of Kaga-Clipse. However, following their centennial anniversary of global peace, an unknown alien threat unleashed a gamma-ray burst that wiped out their technology, killed everything on their planet's western hemisphere, poisoned the atmosphere, and burned a "signal" into the asteroids and comets of their solar system. The resulting collapse of civilization was complete.
As the Clipse rediscovered subsistence agriculture, the marked asteroids began to rain ceaselessly down on the planet, "seeding" it with hostile alien life. In order to combat this new enemy, the Clipse were forced to militarize in turn. As such, thousands of years after the collapse, the Clipse had become an extreme martial culture that worshiped guns and "knew only war", with the planet an eternal battleground between them and the alien horde.
It was during this time that Emperor Calus, in exile aboard his Leviathan, discovered them. He invited the Clipse to join his Loyalists. When they refused, Calus turned to conquest. The Clipse planetary defenses and moon-based interceptors proved no match for his gigantic starship, and his legions invaded the planet itself, led by a Shadow, Valus Nohr. The battle to take the Clipse capital lasted for weeks, but Nohr ultimately destroyed their forces.
Desperate, the Clipse gathered their greatest warriors and launched a boarding action against the Leviathan. Only Rull survived to reach Calus's throne room, bloody and exhausted, where the Emperor casually offered him refreshment and alliance. Bemused, Rull accepted.
Victorious, Calus now began delivering aid to the Clipse homeworld, giving them everything they needed to finally win their endless war. However, he could not repair their atmosphere.
The Sindu are an alien race that dwells in gas giants in the "spinward marches."
When the exiled Emperor Calus discovered the Sindû, he invited them to join his Loyalists. When the Sindû refused, Calus simply conquered them, destroying their entire star-pilot corps save the Ace-Defiant Jarus, who he chose to join the Shadows. After inducting them into his Loyalists, he repaid them with a new fleet of golden interceptors and employed their talents in defense of The Leviathan.