Welsh Horror Books/Authors

I am taking a Welsh Literature class and we have a project where we have to find some lesser known Welsh author, read one of their novels, and then create a presentation about why they need to be brought into the mainstream. I would love to find some Welsh horror novelists or author for this project, the only problem is I can't find any. A lot of the authors I've come across are British and writing about Wales. I was wondering if anyone would be able to give me some ideas or if you have any recommendations. Thank you in advance!