Sins of the Union is a mod for Sins of a Solar Empire II that introduces an immersive experience within the game. Players can command a fleet of Union vessels, enhancing gameplay with new ships, unique dialogue, and custom artwork. The mod features multiple playable Orville ships, ranging from fighters to capital ships, along with tailored combat mechanics that aim to provide a refined gaming experience.

In addition to the new ships, Sins of the Union includes over 150 lines of custom dialogue and sounds, replacing the vanilla soundtrack with the Orville soundtrack. Players can explore custom civilian and military research trees, and enjoy balanced weaponry and ship values to create a lore-friendly environment. Future updates promise to introduce pirate factions and additional playable races, ensuring ongoing development and engagement for players.