Another fantastic species you can use for your kink supernatural OCs - daugrs.
Daugrs are basically like the original vampires, but much less vampiery and much more humans. I am not a big expert on daugrs but here is what I learned from an article written by Edouard Brasey in his “Encyclopedia of the Fantastic”.
Daugrs are a type of Scandinavian undead whose stories were often told in the Nordic sagas between the 12th and 14th centuries. Daugrs are basically just like living beings - they appear and act just like they did when they were alive. In fact you couldn’t tell that they are dead. Except that they are. Their animated corpses never rot and have no sign of death (no palor, no rigor mortis, nothing).
The two other signs with which you can spot a daugr is that 1) while they keep their original personality they become very stubborn (mostly insisting on reclaiming their goods and continuing their life as if nothing happened) 2) they have super-strength. This is the main characteristic of the daugrs, and their main weapon - when heroes come to fight them, it usually ends up with wrestling and other type of combat in which the daugr is much stronger than the human hero.
But here’s where things get interesting: while they look just like their living self, as time goes by the daugrs gain in height and weight. Basically they grow taller and fatter, until they look like overweight giants.
If you want additional info about daugrs:
# They actually are only active during night-time. During the day they return to their funeral mounds/grave to return in a death-like stasis.
# Daugrs cannot enter a house unless they were invited in it at least one time. If they are refused the invitation, they will keep wandering around the house and sometimes climb on the roof.
# Some daugrs can be destroyed by cutting their head off, but others actually survive that and walk around with their head in their arms (one for example used his head to knock on doors and as a weapon to hit people)
# The only definitive way to destroy a daugr is to burn its body to ashes and then dispatch those ashes over running water (a river or the sea).