Isn’t GPT-4o (the multimodal model currently offered by OpenAI) supposed to be able to do things like this?

Don’t get me wrong, I think you would be better served by taking this as a fun exercise to develop your imagination and writing skills. But since it’s fanfic and presumably for personal, non-commercial purposes I would consider what you want to do to be a fair and generally ethical use of the free version of ChatGPT…