If I mention Allah indirectly in a fiction novel, is it haram?

So, I write a novel about a super overpower monster. People think that the enemy is a god, because he can hold more than a billion balls with a single hand. Each ball have the size of the observable universe. For some reason, the main character managed to defeat the enemy. Then human realize that the universe is still exist, without a "God" If that powerful being is not a God, then how strong the God would be? No one can imagine it anymore. After a period of time, they aware that God does exist, but nobody can imagine how it look like, they simply don't know anything about it. If the story end there, I'm pretty sure it's haram. But what if, the main character said this, > "I don't know how to describe it, But I believe that God does exist. > Because the monster we have been fought was very strong, but he is > not a god. I understand that we have a lot of religion on earth, so I > won't force you to believe in my religion (islam, I won't mention it) > I just want to remind you that God exists" My goal is to make the most powerful human character on a fiction novel, but I don't want to surpass or reveal the God. Everything about the God on my novel should be unknown, beyond our imagination. I want to make people realize that humans are small, and only know <99% facts about the world. I also want to expand what people think about the size of the universe. Of course I won't mention Allah on a fiction novel, I believe that's haram, and I want to respect another religion. But I also don't want to make an imaginary god, my God is Allah. Is it haram or not? Can someone explain it to me? if it's haram, do you have any suggestions about what should I fix on my novel so that it won't be haram? Thanks.