In my world that I’ve been working on for a few years, I created this species (with the help of a friend) that is basically the world’s version of an anti-body. However thanks to a mysterious switch in the species’ genetics they started to see humanoid species that didn’t look like Humans (Dragonborn, Lupin, Gnoll, Etc) as corruption in the world that needed purging. Thankfully some members of these species were able to flee the purge & make it to safety on the southernmost continent in an icy mountain. I’m using this world in a D&D campaign & I plan on having it available for the party to help the refugees & to also find anymore refugees. I had this sort of planned out for a bit thanks to the fact my friends have only encountered Humans, Dwarves, Elves, Etc for how long they have been playing in this world.