So, one of my players is having some family issues that will prevent him from playing for a while, so we all decided to hold off until he can play again. As the DM, I decided we should start fresh when he comes back.  new characters, new world, new campaign.  Im very excited about undertaking this task, however, the excess time is leading me to obsess a bit over my campaign and pine over stupid minutia, which has been leading me to writing myself into corners sometimes.  before I give background on my world campaign I need help answering this question:  What types of cities/societies would develop in a world/kingdom like this.

Arcturus is an island kingdom, about the size of Texas, with a giant lake in the middle of it, roughly the size of New Jersey. its surrounded by high cliffs on all sides that lead into near impassible mountains inhabited by recluse dwarves.   Unbeknownst to the rest of the world this island is the world's only supply of mythril, save for a few deposits and/or relics lying about the rest of the world.  the island is thought to be a myth by most as nobody who has seen the island has ever made the trip back to tell about it.  The recluse dwarves that inhabit the mountains will often rescue any traveler that is lost or shipwrecked, and will kidnap any who venture too close to see the island.  The reason for this is because they are protecting an entrance to another plane.  The entrance was sealed off by Lathander the god of birth and renewal, when he came to blows with Shah the goddess of darkness and loss.  being roughly equal in power, Lathander was unable to vanquish her so instead, opened a seal to the other plane and pulled them both in and sealed it from our plane's end.  being gods, they are still able to visit this world be being born as mortals.  Often being born as powerful wizards, Lathander will return to the island and lead the dwarves who help protect the seal. Shah's power is drawn primarily by mortals' knowledge and worship of her.  all knowledge of her existence was eradicated by the dwarves over time.  Though Shah repeatedly is born as a powerful wizard, she can never find the island because it is protected by magic stones created by the dwarves that literally shields the island from the rest of the world ( yeah I stole that from Wonder Woman).  The dwarves essentially hold there kidnapees and rescuees hostage on the island.  They are given the ultimatum of living the rest of their days on the island, or death. The dwarves fear that any witnesses will bring more people back to the island, which in turn will make it easier for Shah to find the island and open the seal so she may return to this plane as a god.  Before any outsiders came to the island there were elves that were native to the island, and have been trapped here.  They tried many times and many ways to escape, including all out war with the dwarves, but the mountains that surround the island were too hard to pass, and the dwarves protected all paths at all costs.

So, at the beginning of this campaign Id like to say the island has been operating under this policy for about 1,000 years.  I'm on the fence as to whether the dwarves do or dont mingle with the island's inhabitants.  Do the people on this island know about Lathander and Shah, or should they be in the dark about it too( afterall, the more people that know about Shah the more powerful she becomes)? I think I'm leaning towards keeping all the inhabitants in the dark about it.  It'd make for a great secret to uncover.  ANYWAY, original point, this is an island of immigrants from all different parts of the world. elves, humans, gnomes, halflings, dwarves. Most were lost at seas or shipwrecked, while plenty of others were boarded by the dwarves.  so there were probably a lot of traders, soldiers, lost settlers, and just general adventurers.  though the island is surrounded by mountains on all sides, there is still plains and forests once you get into the island.  What kind of cities/societies do you think would bloom from these circumstances?  How populated or unpopulated do you think this island would be after 1000 years of this?

i know its kind of a long read but if you've made it this far I'd really appreciate some ideas and/or feedback.

Thanks

I will attempt to organize my thoughts on this.

Roughly texas sized island with a Great lake in the center.  Certainly room for four larger cities, maybe only two of which are high cities of a sort.  The dwarves are of a very Lawful Neutral bent which many of the captive races will likely not appreciate, which could give you plots points for tension between non-dwarves and dwarves.  This duty they have been continuing for a few generations of dwarves, may also be causing younger dwarven generations to chafe under the strictures imposed upon them by the elders.  Do they all still believe that they are actually protecting the world from evil anymore?  I see the dwarves as a militant priesthood, doing their duties even when they are distasteful for the greater good.  Only through eternal vigilance can they prevent the return of the evil queen.

One city would most definitely be a dwarven made citadel, some above ground and most of it below going back into a mountainside or the cliffs themselves.  Though there is still limited access from the other races it is probably something like 75-90% dwarven, not quite off limits but you probably have a good reason if you are there.  The dwarves would be very protective of whatever is in the citadel, outsiders tolerated but not appreciated.

A second would likely be much more metropolitan and have a relatively even mix of the races on the island, although probably a very low presence by the elves if they are still antagonistic towards the dwarves for their essential imprisonment on the island.  The elven presence in this city might be a low key, intelligence gathering subset still trying to subvert the dwarves and escape this island.  Elves are meant to be free, not incarcerated on a glorified prison island.  Whatever other races you would like populating this one would likely share control and power relatively evenly with the dwarves with power shifting back and forth between the groups.

Third would be a much more rural 'city' perhaps sprawling along the lakeside, growing larger and spreading along the shore over time with little city planning.  This I would put on the opposite side of the lake from wherever the dwarven stronghold/citadel would be.  An attempt to get away from the controlling aspects of their dwarven wardens.  I don't see the dwarves being truly oppressive (other than the mandate of stay or die) but certainly controlling of other aspects of life that the mishmash of other races might not like.

The fourth would be the hidden city controlled by elves but actively hidden from the dwarves, a headquarters for a resistance group that desperately wants to leave this prison and explore the greater world.  Suspicious of outsiders to protect their hidden place (or perhaps it is semi mobile moving periodically to protect its secrets) they probably employ similar tactics to the dwarves of stay or die.  At least stay till they believe you are not going to betray them to the dwarves.  Though perhaps not paranoid they would be wary, maybe quietly following those that have left and if necessary handling information leaks.

I also see it as having a number of outposts around the periphery of the island to handle wayward ships, their locations are likely well kept secrets to keep people from trying to leave without permission.  You mentioned the portal to another plane was closed behind the gods, perhaps they were just broken and still pop up in odd areas from time to time, not large enough for a god to come through but maybe enough for some other denizens to cross over.  Cults that worship Shah may find these portals and pray for their release from their prison island.  

Use what you will, hopefully it at least gives you some ideas to capitalize on.

Thank you so much.  I appreciate your ideas and insight.  i like the idea of the younger dwarves "losing faith", that thought had actually occurred to me.  After 1000 years, how can you know for sure that what you're worshiping is legit without any proof? I also dig the idea of an ever-moving city to harbor a resistance group.  again. Thanks, this helps me get the ball rolling on writing again.

Get those creative juices flowing, and feel free to ask for input.

Good luck and have fun.

just for the sake of juxtaposition, how do you think the island would've developed if the dwarves just let people in and then left them to their own devices, and didn't interact with the inhabitants at all?

Very hands off?  in a single word, wary.  Maybe seen as boogeymen of sorts, they come and go as they please maybe not avoiding the inhabitants but not directly interacting with them unless necessary.  Talked about almost in a strange mixture of awe and wonder, wondering what they do in their strongholds everyday.  

I would presume that certain racial groups would still congregate together in some of the cities, maybe one or two dominant races per city.  Not that others are unwelcome but it could end up like china town kinds of districts.  A place where they can hold onto the faiths and their cultural ties.  I would still advocate one extremely metropolitan city, where most of the races mix fairly equally, which might be a city where some of the younger dwarves "buck tradition" and interact with the inhabitants of the isle.

As a side note there could be a ruined dwarven fortification from the sealing of the planar portal that is entirely offlimits to everyone, dwarves included giving a more ominous tone to the keepers of the island.

You're the bomb and I appreciate you.

I truly enjoy this, even if none of my ideas get utilized I bet they have stirred up some great ideas in other peoples heads.  Not to mention it gets me thinking in interesting ways for my own game.

I had a blast reading this! :) Just imagining all of these cities, people, the kidnapping and such sounds like a wonderful storyline. When I read the party about the younger dwarves losing faith fire some reason I imagined them as kids "being brave" and seeing who could get closer to the portal... I hope everything turns out awesome for you.