I like to read fantasy novels with a badass ML who happens to be a supernatural being. Demons, vampires, werewolf, gods, etc... Any suggestions, please?
The Spearmaster and the Black Cat - The MC here is a Vampire, and Spoiler: A bit later a soul Eating Vampire
I know a lot of BL novels with ML is a ghost. Other supernatural beings idk Are you interested in BL? LOL
Devil May Cry fanfiction, Dante, Nero and Virgil are badass. On ff.net of course, not that crap webnovel.com
The Zombie Knight Saga. MC makes a contract with a Reaper, and becomes an Undead. This... doesn't mean that he's some kind of shambling Zombie, but rather that, so long as his Reaper continues to exist, he's effectively immortal, can have his body reconstructed from scratch, and has powers based around some theme that is seemingly random. The MC's theme is either Iron or Steel (I can't remember which one), so he can literally make steel bars, armour and weapons from nothing. He Who Fights With Monsters may be considered to fit on a technicality, as the MC got Isekai'd and became an Outworlder, a term used for anyone who survived losing their body being pulled through the Aether that separates universes and made themselves a new body out of magical energies when they reach a reality on the other side. But, for the most part, he's practically human, and there are actual Vampires and the like running around, so you may want to disqualify this for that reason.