Hi! I struggle with the same thing when it comes to incorporating God into fantasy stories. It doesn’t help that there are hardly any Christian fantasies out there, so there aren’t a whole lot of examples to go off of.
As everyone else has already said, probably the best way to incorporate God into you stories is weave His attributes into it. Weaving His attributes into it is sure to bring your story depth and life, as well as bringing God glory through your story. ( Hey, I rhymed! 😉
Another way that I’ve seen others do to put God into their stories is include Him in there, but call Him by another name. For example, I’ve been reading these Christian fantasy stories, The Old Tree series by Tricia Martin, that has God and Jesus playing major roles in her books, but under different names. They are still the Father and the Son, just under a different name. C.S. Lewis does this also, giving Jesus the name of Aslan in his series, The Chronicles of Narnia.
And lastly, what I’ve been doing for my own fantasy story is mention that the land is ruled by a Higher Authority, or make comments within it about there being a God who rules the land, while not directly mentioning God Himself. Those are subtle hints about God, without becoming too preachy about Him.
I hope this helps you! God bless!!
"If life were short, where would all the adventures be?"
"We're all mad here."