Galactic Civilizations 2: Twilight of the Arnor — According to the backstory of the main campaign of the game, the Drengin and Korath races are at war, with the latter wanting to destroy, and the former simply enslaving the Galaxy. Presumably, both sides are being manipulated by the Dread Lords, who are biding their time in preparation for the next attack. Meanwhile, Earth is isolated and safe behind an impenetrable barrier, while its once-mighty fleet seeks ways to end the threat of the Dreadlord once and for all.
As the game's main campaign progresses, a single Terran Alliance ship is revealed to be confronted by one of the Arnors, a race of creatures descended from the same creatures as the Dreadlords, but taken a gentler path. According to the game's plot, humans then learn the key to defeating the Dread Lords. This includes massive Death Star-like ships called Terror Stars.