How’s this for a idea for a Fantasy World?

I’ve been using this world in a few RPGs I’ve run, but im thinking of setting my next campaign in it and I think it would make a good place to set a story or something too. <br><br><br>So the idea is that it’s a fantasy world that was invaded by demons and other monsters from another realm, but demons were weak against iron and so the humans used iron to drive them back. However, magic existed in the world and was powered by nature. <br>In order to power magic, you had to have forests or other natural places to draw power from. So the humans had a choice, they could use magic to drive the demons out, but would lose any of their cities, towns and villages built in natural places. Alternatively they could use iron to create weapons and armor and advance technology to drive out the demons and keep the cities and towns. <br>In the end, the humans decided to do both and this is where the modern world’s countries come from. <br>The magic users live in nature, in forests, mountains, swamps, tundras, oceans or deserts and have magic, but don’t really use iron. The non magic users live in the cities and towns and use iron and technology to make things easier for them. <br>This creates a weird dynamic, where magic users and non magic users don’t often interact and many don’t know how the others live. <br>I’ve set the world in the early 19th century for technology level, but for instance, magic users have a harder time keeping a magic item that is part iron, magic users who live in the ocean have been able to explore the ocean floor without any sort of scuba gear, because magic can protect them. <br>I’d love to hear feedback or suggestions.