I don't know how familiar you guys are with Pokemon around here. But basically my fan made region has a very important world wonder. Several times in canon, in multiple forms of media (both the games/anime and films) they talk about pokemon generating a 'mysterious energy' when they evolve. Some characters even theorize that this energy is the exact cause of their evolution. The detail I'm yet to sort out, is WHY this font of energy exists explicitly in this region, and why the rest of the world doesn't know about it yet. The other thing I need to sort out is why the region is kind of a hot pot of all the other regions. Each of the gym leaders use a different mechanic unique to the region from which they originate. (So a Galar Region Gym leader would use Gigantimax gimmick etc) I need a good enough reason for the region to be a melting pot of sorts.
Maybe it's the site where all the elder gods battled to the death and wiped each other out of existence, and some of their magic remains there. Magicks of many different gods, which explains the melting pot aspect, or at least why there are multiple different kinds of strange energies.
Lol, what a coincidence, I was watching the dumpster fire that is Violet and Scarlet earlier today, it's sad how low they've fallen because I really liked Pokemon back when I was younger. Honestly, when it comes to Pokemon, there isn't a whole lot of lore. I bet the Pokemon company knows as much about the "evolution energy" as the rest of us. I'm looking at you, GS Ball! But alright, let's talk about energy. When you mention energy, I can't help but turn physics mode on and say that energy doesn't get generated... as in... created. It merely changes from one form to another, even when it is "spent". This means to me that Pokemon have some biological process that converts some form of existing energy in their body into this another form of mysterious energy. Let's call it Energy X to simplify things. Since Pokemon have some, probably limited, ability to produce Energy X, then all you need in your region is some kind of source that naturally produces it. Say... flowers... or some core hidden beneath the ground. Or a legendary Pokemon. Or... make it dark and say that this energy is a by-product of death, and that some hundred years ago, there was an incredible bloodshed in the land that made the levels of Energy X very dense within the region. Xoic also made a very good suggestion that you are likely to hear within the limits such a franchise has. But further than that, I'd ask why you're so stuck up on coming up with a reason if it doesn't really tie up to anything. Even official Pokemon storylines blurt out a bunch of nonsense, never to touch or explain it again. That's because they know what to focus on. So, what are you focusing on? What exactly are you even working on? Is this a ROM Hack? Or a narrative story?
Make it a bermuda triangle region that's between all the other regions and sucks people in. Solves both of your problems. 1) why this font of energy exists: because it's the bermuda triangle and weird shit goes on there. 2) why the rest of the world doesn't know about it yet: because it's the bermuda triangle and it's untrackable. 3) why it's a hotpot of different regions: because it's the bermuda triangle and it's sucking people in who travel over/near it. (yes, I know irl the bermuda triangle isn't that mysterious but shh.) Also what Xoic and Psy said: pokemon lore ain't that deep and all you really need to do is say "there's a legendary god-ish pokemon that created this region and..." idk, likes to hop in between dimensions so created a world that's inbetween dimensions that sucks people in??? was a naive and/or jealous copycat and didn't know how to create its own region so just steals people from other regions to inhabit its own region??? doesn't like humans so created their own region on another plane and people keep tripping into it?? Just make something up and no one will think that deep on it.
The Region is actually a bunch of floating islands (held up by artificial tech/pokemon, not magic or nothing) so it's very similar to bermuda (in mythology) People and pokemon travel from around the world to and from the islands, but nobody knows exactly WHERE it is except the pilots who pilot the jets to the region. I figured it could be a pokemon, I just don't have any idea what kind of pokemon I could make it be. I do like the idea of it being eldritch horrors. The fact that there's a physical site where this energy wells up from, maybe there was a pokemon that generated that energy and it just died there. (maybe from fighting Arceus I guess?) The extreme amounts of that energy could be why all the regional gimmicks are possible in the region too. But only certain islands because the other mythical mons are resting there. There's already a mon responsible for gigantimaxing, but I could always make a 'good guy' version of it (since the one in Galar is basically evil)
