Stellaris Nemesis is an expansion of Stellaris which means the base game Stellaris is needed to play it. Nemesis is allowing players to destabilize the galaxy by bringing in some espionage tools which you can use for chaos or control.

• Become the Galactic Custodian where you get emergency powers during a crisis.
• Espionage is added to the game with new spy tools. The knowledge that you acquire will always give you the upper hand.
• New operations are available as your Infiltration Level grows.
• New ship sets are available that will make your ships as imposing as ever.