I'm making a strategy RPG, and I'm having trouble justifying the gameplay's core premise in light of some recent developments in the world I've built around it, and I need some help filling in the gaps.
The main premise of the game is that, due to mankind hunting dragons so close to extinction that they needed to flee the planet entirely, the ecosystem of Earth was so completely devastated that the entire planet is now a desert wasteland. There is only one source of water remaining anywhere, and the last bastion of civilization had been built around it: A large tower with a magical crystal on top, which constantly gushes out water like a waterfall. It's guarded by a church that preaches the ways of the ancient dragons in the hopes that one day they will return to set things right, as they promised the few virtuous humans they would one day.
The main character is a member of the church's military, a holy knight who leads a troop tasked with defending caravans as they deliver water to the most remote villages that are too far removed from the oasis in the center. Gameplay revolves around fighting people who would attack the caravans and steal the water for themselves, and if the caravan is ever destroyed, it's game over.
Here's the problem: if there's enough water for everyone living in this desert, why do so many people live so far away from it that they need it delivered by caravan? Why doesn't everyone just live close either to the oasis, or to manmade rivers that flow from it?
This is doubly a problem because the entire civilization is completely artificial. The entire premise on which it was built is a lie. Humans didn't destroy the Earth at all. Most of the Earth is entirely fine, and this "desert" the humans live in is actually completely fake. That magical water-making gem doesn't actually make water at all. It just absorbs all of the rainfall in a massive area and concentrates it all into one place, leaving everywhere else for miles and miles around a barren sandy wasteland. In reality, dragons invaded the planet thousands of years ago and destroyed nearly the entire human race. What little of humanity remains is kept alive in this fake desert essentially as livestock, so that the dragons can pick a portion of them to parasitize and wear like meatsuits so that they can survive in the Earth's atmosphere. The reason there's only one source of water in the whole desert is so that they can make sure all of the water humans drink is laced with a drug that suppresses the magical powers that humans no longer even remember they all innately have.
The dragons running the church, therefore, who engineered this entire civilization thousands of years ago, have a vested interest in keeping every human in this desert hydrated. Because in some rare cases, the magic-suppressing drug in the water wears off before you die of dehydration, and if that happened in the wrong place, the church's lies about the origins of magic would be completely exposed. So I'm suddenly realizing it wouldn't make any sense whatsoever, either by human reasoning or dragon reasoning, for entire villages to live in constant danger of running out of water, when there's enough water for everyone easily if they simply live by rivers.
Yes, the dragons want most of humanity to live in a constant state of hardship and desperation to make them more desperate and deferential to the church and to maximize the guilt they feel over their ancestors' alleged crimes against the great dragons, but they also need to make sure human magic, and the knowledge that humans can even do it, stays suppressed.
But if humans have constant easy access to water... I also have to come up with a completely different premise for what the heroes are doing and why they need to spend every mission defending an unarmed, slow wagon. Which would be less than pleasant.
Why would there be villages so far away from sources of water, and why would the dragons in the church allow these villages to exist?