I got tired of planar travel and supernatural events/creatures being so rare in a lot of the games I've played that I decided to go about this differently. Instead of traveling *to* those planes and hard to reach realities via portal, spell, wierdo aphrodisiac or artifact... sometimes those planes bubble up in places and plant a lil' old seed right on the prime material. Now, it might be harder for certain plains, lookin' at you Abyss/9 Hells, because the forces of good are *actively curtailing ANY encroachment by those planes* they may instead burp. Or something. Leave a cute lil' chained devil or vrock or wierdo aberration, who knows! This can cause problems for people living in remote areas, but typically a village could band together and take out a VERY weak creature from those places.
However, sometimes entire zones either fall under sway of those "Planar Bubbles" and either become "permanent," occasionally spawn much more dangerous or more numerous creatures, or might even be a seamless part of that plane ON the good ol' prime material. Queue hags abducting children, demons having a midnight snack on your cow and cowherd, but also a friendly neighborhood Kirin has suddenly come to bless your village/kingdom with some celestial assistance. It doesn't have to be purely doom and gloom you know... it's just easier for your characters to find conflict if it is :)
This allows for the world to have a great diversity in encounters and also allows for certain "natural" places to become much more fantastic. Take a graveyard for example. It's a place with a lot of dead folks. Got it. Naturally, there may be some collection of negative energy there. Maybe it's the capital city's graveyard and the cleric in charge of blessing the grounds once every year or so has died several years ago and... well... maybe someone forgot it was a thing. "It's been decades since we had any trouble from the graveyard, I'm sure it'll be fine for a few years."
One banshee, twenty wights and a handful of ghouls later and they got the idea.... <------ that example doesn't need to be what happens out the get-go. You can of course manifest the dangers as quickly or slowly as you want. Just try to make it proportional if you're using an example similar to this. It was the graveyard for THE CAPITAL. Like... 30,000-50,000 people may live there, OR MORE depending on how you do things. Keep things somewhat proportional and you're golden.
Just so it's clear:
In any case, more will be worked on soon. Cool.
Oh, Demi-Gods roam the land and act as intermediaries for the Greater Gods (the true Multiversal deities from any of your favored settings). They do things. They're tangible. And they're visible proof of the divine in this setting. Aloof gods are a trope I'm tired of frankly. I get that they can literally Deus Ex Machina all over your world if you're not careful, but that's your responsibility ;D
Also, I play a lot of videogames and am influenced by comics/anime/history/life so you may or may not see references/influences to/from Diablo, Guild Wars, Final Fantasy, the Elder Scrolls and many, many more.