Would it be a bad idea to make up fictional Catholic Saints for things that don’t exist in the real world?

For context, I’m writing a novel set in a world almost identical to our own in the early 20th century, except the supernatural is very much real and prevalent in people’s lives. The Church is of course heavily involved in the suppression of the occult and evil creatures, hunting down things like vampires and fae in addition to demons. I’m wondering then, if it would be a bad idea to invent fictional saints to be the patron of fields such as vampire hunters, or of the mystic arts in a world where there is a clear distinction between good and evil magic. I’m wondering, would this be a bad idea? Would it simply be better to assign qualities to already existing historical saints? I’m a man of faith, and the last thing I would want is to offend God or His Church on Earth, so I need the opinion of the fellow faithful.