Been thinking about worlds I might like to use for a potential TTRPG, and here’s one idea.

Eight years ago, the demon invasion began. No part of the world was untouched by it; entire landscapes have changed beyond recognition. But now it’s over. The portals have closed and it’s time to pick up the pieces.

No one is sure which side opened the first portal, but it’s generally thought to have been an accident. A small part of the demon world was overlaid onto this one, inhabitants and all.

The act of being portaled here changed them. On the other side, demons have no physical form, but gained them in coming here. They found this to their liking.

A few more portals opened, and they were welcomed at first, for the most part. But then more came, and more, and more. All of them came to this world through this portal, every single one.

Some found themselves in places they were not welcome, where this world’s people were fearful or simply overwhelmed by their numbers, but the demons had the Three Powers to keep them from being driven off: the Power of Form, the Power of the Land, and the Power of the Flame.

The Power of the Flame came from their own land. Every demon could twist fire and lightning to their will, and many were quick to use it on those who they felt had wronged them, or were in their way. This world responded with the Power of the Sea and the Sky, and drowned their flames, but at a terrible cost.

The Power of the Land came from the bridge between the two worlds. Demon and wizard alike reshaped mountains and drove entire plains into the sea.

The Power of Form came from the demons’ connection to this world, gathered through their horns, and granted them the Two Forms all would come to know. When the portals closed, it was the only one of the Three Powers left to them.

Thus, a demon comes in one of two forms. The first is the Ghost Form, in which they are only half way solid, and can pass through almost any barrier with effort. Only metal can truly stop or contain them. This is the closest to their original state of being in their own world. When they had the Power of the Flame, it was strongest in this form, but now the only creature a Ghost demon can harm is another demon.

The second is the Land Form. This superficially resembles an an animal each individual demon chose when they came here, but might be seen on two, four, or even more legs, wild and outlandish in colour, and always, always with horns. This is the form a demon would most likely be seen in, as it is the most comfortable for them.

So, here you are. The portals have closed, and there’s no way back to your original world. You may or may not have even wanted to come here in the first place. None of the natives trust you, and you’re not sure about most of the other demons still here either. So now what?