The character card doesn’t need to contain any information. The main focus is on building the world lore—define the rules of the world you want. As for characters, you can set up the one you’ll control directly in the world book, including details like name, age, gender, personality, and so on.
If you want the LLM to be more creative, avoid giving it a fixed storyline. Just let it understand what kind of world it is simulating and what exists within it. Of course, if you get bored with your current setting, you can simply have the LLM take you to other worlds, as long as it has the knowledge. For example, you could explore worlds like Resident Evil, the Avengers universe, a cyberpunk setting, and so on. (The LLM likely knows many worlds—far more than we do.)
No preset structure is required. Anything you want the LLM to do can also be written into the world book entries, which can be configured as global rules or triggered by specific keywords, depending on your needs.