It was only known as the Mothership to its people.

It was an unbelievable large vessel, almost the size of a mountain. It was shaped almost like a saucer, pure white and silver in its color.

And it carried the minds of the sole remaining survivors of an alien race, as they traveled from planet to planet, mining its resources to power their Mothership so it could stay running.

And now, it had arrived in Fantasia, a medieval world torn in conflict between all the various races in it. And it was the very first planet they visited that possessed Mana, allowing its inhabitants to use and employ magics in their daily lives.

Fortunately for Fantasia, the Mothership had a rule it always obeyed. If a planet had sapient creatures living on it, they would have to ask for their permission before grabbing their resources. Only if all negotiations broke down and when the Mothership couldn't survive one other trip to a different planet, they would resort to pillaging the planet by force.

And so the Mothership sent their agents, either AIs or digitized minds, linked to an android body, to roam the planet and make deals with the native populations. They would become its ambassadors, bridging alliances and making trades with them, or, if they felt that they were unworthy for such an arrangement, they could bring their case to the Mother Brain, the supreme AI that ruled over the Mothership, for them to be granted permission of laying waste to them.

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Welcome to my interest check. This is still more in the idea phase than a solid setting and RP idea but I thought I'd post it to the interest check just to see how many people are interested.

Basically this would be sorta a science vs magic kind of story, with the aliens in the side of science. I'm not sure if players would want to play other than the aliens though, especially since they're kinda the ones moving the plot along. Though I guess you can play as the fantasy side going to the Mothership to investigate it.

The default setting I have in mind for the fantasy world is going to be like your typical Japanese isekai fantasy setting. Humans are in conflict with non-humans, especially against the demon race. The human church has an anti non-human teachings, viewing them as inferior heretics. Slavery still exists, with both sides having both human and non-human slaves (with the beastmen being most common). Dwarves and elves hate each other while beastmen are torn between supporting the humans or the demons; both sides viewing them just as an easy source of slave workers with their super strength. Lots of corrupt folks on all sides in short.

Their technology level is medieval with some magic tools in use, with demons using most of them. Elves could manipulate the growth of plants. Dwarves have their steam devices whose secrets they never shared with anyone. Beastmen are the most primitive, living nomadically off hunting monsters, as they believed settling down and becoming farmers to be a dishonorable act.

The aliens would ask for permission to set up shop in mana rich lands where they would proceed to suck it all up to be stored as energy for their ship. They could offer all sorts of things in return, from their technology to passage for mind upload into their paradise-like cyberspace.

Their Mothership would land in the middle of the Great Wasteland, a scorched and empty battlefield destroyed by generations of combats between humans and demons.

Society inside the Mothership's cyberspace is mostly free, with most of the aliens living in a simulated, idealized version of their home world without having any need to work. Going to the real world is strictly regulated however. They knew they had landed on a new planet but as much as some of them wanted to sightsee, only chosen agents trained in diplomacy and combat were allowed to do so. They didn't want to risk any diplomatic incident if untrained civilians were to be unleashed to the real world.

I'd like it for players to worldbuild their part of the fantasy world, even if they're just playing as the aliens. The aliens would send their agents to every corner of the world after all. And feel free to ask anything about the setting.