I think one of the most common bits of advice that a writer receives is: write what you know.
I’m a literal person. In more than one sense. I write paranormal. And I’ve often thought of that tip. I, personally, don’t know any vampires. Or werewolves. Or witches for that matter. But I do write about them.
Then I think of all those authors who write about murderers, or violent deaths. How many of them actually know a serial killer? Not many I bet.
I think that writers are told that to make writing easier. And believable. A blank page can be one of the most intimidating things. If you start writing about things that you know, you already have a base of knowledge to start with.
However, I believe that little gem should be lengthened to say: write what you know, enjoy or are passionate about.
I may not actually know any demons, but I certainly do enjoy writing about them. I research them, drawing from myths and old manuscripts that portray them. And I make up backgrounds and realms about them. I write fiction. I can do that. And I don’t have to have personal knowledge of them.
What I do need are believable characters, an interesting plot and a story that will draw a reader in and make them cheer for the people – or creatures – in my book. If I am passionate about my characters then – hopefully – that passion will come across in my writing. And my story will be all that much the better for it.