AI-Created Art Isn’t Copyrightable, U.S. Judge Says in Ruling That Could Give Hollywood Studios Pause
(www.hollywoodreporter.com)
The concepts contained within a copyrighted work are not themselves copyrighted. It's impossible to copyright an idea. Fair use doesn't even enter into it, you can read a copyrighted work and learn something from it and later use that learning with no restrictions whatsoever.