Creating an Original Expletive
My main character is originally from the Underworld. It's a YA book, so I try to keep to the mild curses and most of the time he just says 'damn'. But I can't tell you how often I get a critique that says, "You should create a new kind of expletive for him. I wonder what kind of curse a guy from the Underworld would use."
But the thing is, I have no clue what expletives he would use either. The Underworld he lives in is much like Dante's Divine Comedy, just to give you a thought. Hell is more commonly called "The Pit" by him, and The Pit is a swirling vortex in the middle of the River Phlegathon, also known as the river of fire and blood.
Most of the creatures in the Divine Comedy are also in this book too, but they don't play a big role. I have the world down, but I really have no clue what they might say as an expletive. How do I go about this?
(One thing you need to understand though is that he's from the Underworld. That doesn't mean he's from Hell. He can see Hell from his bedroom, but he can also see Heaven too. I get that misconception a lot...)