"著者はその本の中で宇宙の神のようでなければならない。"

Simplified Meaning:

When a writer creates a story, they need to have complete control over everything in it, like how people think God has control over everything in the world. Imagine you're playing a game where you get to decide the rules, the characters, and what happens next. You choose how the characters look, what they say, and how they act. If you make all these decisions carefully, the story will make sense and be interesting to read. For example, when J.K. Rowling wrote Harry Potter, she decided everything about the magical world, Hogwarts, and the characters. Because she controlled all these details, readers found the story believable and exciting. If she hadn’t done this, the story might not have felt as real or compelling. So, if you’re writing your own story, think about every detail and make sure it fits together well. This will help your readers understand and enjoy your work much more, just like a well-ordered universe is easier to live in than chaos. By being like "God" in your book, you're in charge of creating an engaging and coherent world for your readers.