One of the things I really like about writing The Paladin is that I get to add my own touch to the gallery of classical monsters. Of course I can't write a supernatural fantasy novel without touching on demons, vampires, werewolves, etc... they're staples of the genre. They'd be conspicuous through their absence. That doesn't mean I can't add in my own.
So far, I've added three unique creatures to my story. It's been great playing with them, figuring out how they different from established creatures, and plotting out their importance. I've had to create lore from scratch, filling out a backstory for an entire species. And best off all, I still have three or four more waiting in the wings.
I think the hardest part is making them stand out as unique without being so far out in left field that they're just pointless. You have to accept that certain things, while being part of other monsters, are not the complete essence of those creatures. For example, you can have blood sucking monsters that aren't vampires. There's more to a vampire than simple draining the blood from their victims. In real life, more than one creature can lay claim to being a blood sucker. Of course we have mosquitoes and vampire bats, but also fleas, beg bugs, leeches, vampire finches, lampreys, and ox peckers. There's no reason your monster can't drink blood, just make sure they stand out.
I have to say, as I'm writing this, I'm very excited to see this novel come out so I can introduce the world to some of my creations. My characters, my world, and of course, my monsters.
Don't forget to be awesome!
Keep your eyes open for my debut novel, The Paladin.