UTDR world building/headcanon. (There's too much overlap for me to decide.)
Human & Monster cultures prewar:
Humans worship 7 gods representing the main 7 human soul types, there are more but they all descend from the original seven.
Very strong willed humans can learn to wheeled magical weapons & use spells. While it's very rare a human can be born with natural magical abilities, it can happen. Though it's very rare & only rumored. The abilities mentioned are: the ability to save & load time, resurrection, & emitting light from ones soul.
Monster religion is very old but they follow the prophecy of the Delta rune & the angel. Monsters originate from magic given physical form, if that form was given by the angel is unclear. Sometimes there's there's 3 heros of legend on rare occasions it's 4. They also have important figures such as the ice mage, fire spells are equally as important. Fire, light, warmth, was a gift from the angel. Ice, cold, is the absence of warmth.
Hybrids (this one is just silly nonsense btw):
In places where humans & Monsters cohabitated they were the norm. Think things like: werewolves, vampires, even elves. When the war broke out it was very very hard to be one of these creatures, if you looked to monstrous you'd be killed or sealed underground with the rest of the monsters. If you looked to humanoid you had to be careful & secretive, if you wanted to stay on the surface you've never see your family again.
Most hybrid bloodlines during Frisk's time are either too integrated w/ monster bloodlines to be distinct anymore. The ones left on the surface are either dead, too integrated w/ human bloodlines, or immortal & hidden away.
I'm making this a series now I guess?
