We're establishing a fortress in the same world as the previous one. I'm going about setting the thing up now, but it will take a while.
Edit: It will still be recognizable as a Sparkgear game.
Edit2: I wanted to do some adventuring in this world to check out the ruins of the fortress. The task of getting to the fortress, however, is a bit difficult, as I haven't played adventure mode before for any significant period of time.
Edit3: I've done a few test runs for an adventurer in the Sparkgears world. I could do an exploratory tour of Sparkgear XIII for you, but it will not be possible to do as much as I would hope. The trouble is that the area surrounding the place, the GREATER area including the other mountain range is utterly devoid of moving creatures besides small animals, that I don't think you can eat unless you get REALLY hungry, there is a distinctive lack of any animals, even weak ones, that could cause any fun, when roaming around the outside. I have only run into one kind of creature: Humans. That is, unless you get to Sparkgear. DF adventure mode is kind of screwed until you get the ability to forage from shrubs, or fish, and the like. There are human settlements around Sparkgear, and you have to start at those in order to get to the place. That is do-able, but I can confirm I have had NO combat.
I do not think the fact that the demons are trapped in an adamantine tube will be respected once I get to the fortress. The place is likely to be a crazy mess inside, and full of hostiles.
Because of this, I have decided that Sparkgear and its contents are better left to a future reclaim. I'm now going to focus on setting up the fortresses the way I want them.