Ah yes...its funny, I'm in a Game Design class and the basics is to ask questions...which I forgot to do in my case
It's embarrassing...
Ok, let's see here...
1. and 2.
Why was the Dungeon built...hmm...Alright, how about it's being built over an older dungeon in which the upper floors needed remodeling due to all the adventurers coming in looking for treasure over the course of generation after generation (Sounds as a joke, but if someone goes to all the trouble to make a dungeon, and they're still alive, they want it to at least look nice
). The original dungeon itself was built within the now abandoned lair of an Elder Green Dragon. The Dragon itself has not been seen for generations. However, the main boss, lets call him Bob now, is the heir to a massive fortune he inherits from generations pasts. The treasure he has is actually what still remains from the stash the Dragon left behind. So Bob is 'refurnishing' the dungeon with new traps and putting in new enemies. In a sense he's 'refreshing' the dungeon. He does this not for adventurers, but because the items he has locked away beneath the upper floors are too valuable to be left anywhere else. The top floor or two are simply there to make it seem too easy and thus turn away more determined adventurers (that's Bob's thought anyway).
So, the dungeon is being built to keep the secret treasure beneath it safe from adventurers. Simple enough for now. And as a quick note, they refresh the dungeon about 2-3 times a generation due to the severe lack of adventurers, we are talking about a valley in the middle of nowhere.
Now for 3...Why would a man who is using his fortune to uphold his family tradition of keeping the dungeon safe leave his slaves for long enough time for the slaves to not only escape but use the resources left behind to create a small village...I've got it! It changes the story just a tad bit, but it works...
Alright, so Bob is the evil guy calling the shots at the dungeon sight...But, after the entrance of the cave collapses he find himself trapped inside the dungeon too! His cohorts on the outside know he's trapped, or worse, dead (and when the slaves find out he's inside the dungeon, he may well be dead). So, when Bob's cohorts leave, they're returning the Bob's father...the man who gave Bob the task of 'refreshing' the dungeon! So when Bob's father hears the news (he lives really far away. Like, really far) he panics for his sons life and orders a large portion of his guards to save his son. And thus an oncoming army that the players will find out about later.
Whew...tough work...alright...now for 4.
The slaves themselves come from small villages and towns from across the land, a few taken here and there, secretly so as not to arouse suspicion. Most of the slaves are just that though, slaves. Bought and traded, eventually ending up here. This will give the players the main community of their village, people who want to stay and settler, out of harms way of the whip and beatings. But the ones who came from families and had lives want to return to them. This way after the town has grown enough supplies and can live on it's own peacefully for now in the valley, these npc's that had lives will gather what they can, and leave. This will be when the players themselves leave the village, after all their work is done and they are not needed. The village community will encourage that the players go out and make a name for themselves in other towns as they did in this one.
The majority of encounter in the top floor of the dungeon can be the guards ordered to watch the slaves. As the slaves revolt after they realize what's happening, the guards will try and barricade themselves in rooms, using the few archers inside to keep the slaves away. This is one way the players will then be able to get weapons and armor. After they've settled with most of the guards, they could try their hand at a few 'prize' rooms that have some treasure and maybe one lesser magic object to make them happy.
So that's back story, reasons for dungeon, reasons for army coming, where slaves came from, and item issues.
I want to thank you guys so very much for helping me with this. I know I seem a bit rash and really annoying, but it's something I'm really excited about and I want to get this right as best I can. It means a lot that I can get help from experienced people like you guys and it means a lot, criticism on my work and all.