The Great War for Alpha Centauri

The year is 2156, Humanity reached the stars a long time ago, and is now a dominant power in the Galaxy, however, before this, they were a weak nation, that had just discovered their first, and eternal rival, the Sulisi, a race of Snail-Like aliens. They had colonized the claimed human system of Alpha Centauri, Humanity would go on to take this system by force, conquering them, but what they hadn’t known was that multiple nations of Sulisi were spread across the Galaxy, mostly consisting of alternating ideologies from one another. When a Galactic Community was formed was only then when the Humans had learned their mistakes, multiple nationalistic groups of Sulisi had believed that the system of Alpha Centauri belonged to the Sulisi, which has begun a Great War between Humanity and the Sulisian nations. However, many others are using this war as an opportunity to gain power, and influence people… (This scenario is loosely based off of my modded Stellaris play through, but with multiple different changes, essentially turning it into its own thing.)