24XX The Extropic Sphere

There is an ancient, decaying alien megastructure surrounding the star at the center of this system. It’s something like a Dyson sphere, if a Dyson sphere were made of self-organizing bio-mechanical metamaterials that could be used for just about anything and the most advanced tech anyone has ever seen. Only the driven or desperate venture there. Lethal automated security systems and combat bots, all of it open to hard vacuum. And if you meet anyone there? Shoot first and don’t stop until they’re dead. They’re worse than The Sphere because they’re just. Like. You.