A God who knows how to create a universe will also know how to keep a proof of his existence in the created world. And he will also know how to make his presence known to human individuals.
Now let us suppose that this God has created the universe but that he has failed to keep any proof of his existence in the created world. Neither has he ever revealed his presence to anybody. In such a case no one will ever know that there is such a God and man will believe in as many false gods and goddesses as possible as they have done in the early ages of human history.