I've no idea around the disaster part so obviously I'm happy with not going with that. I'm also happy sort of... starting again as it's been so DAMN long that I honestly can't remember fine details and I think we could make it better this time.
I'm very happy with starting with the Merhites crawling back up. I found the map we had once upon a time XD Not really sure how the Below Ground exactly worked but now I'm just imagining MASSIVE huge cavernous world with underground lakes and craziness where Antul is - bit like this, this (ignoring the spaceships unless we had a steampunk air in it and made flying boats but you know), this which makes me think there is a lot of... other down there, it's kind of like the pit the above throw everything they don't like in and the Demos have made themselves of the rulers of that and now have their eyes on the above.
Thoughts currently are:
● Always been a war between below/above no matter who is in charge. Merhites/Demos been in charge long, long, long time. ● Ten years ago something biiig happened which basically sealed the Demos and others down there but in the process near enough destroyed the Merhites. Perhaps it was done as the Demos have a lot of very, very powerful creatures on their side who just... not good for the mortal realm and so the Merhites saw it as something like a last ditch attempt. It sort of brought peace: the Demos/darkness was trapped and everything was cut off. In my head Issandria has been off in the mortal realm for about ten years, recovering from her injuries. Image in my head where someone comes to get her and let her know that the Demos are making a move again. ● I know originally a lot of movement was due to father's being killed but that could already have been done and gone? With Vorian already king perhaps.
So with that we could easily keep everyone with their basic history set up and the world as well without the... mess it had become.