Can I expand my own literary theory of the Black Zodiac without copyright prosecution?

Have my eye on a 12 part series of books but dont want to infringe on any copyright (if there are). Think I can add an entirely wicked spin onto the black zodiac if given the chance....Can I expand my own literary theory of the Black Zodiac without copyright prosecution?
By the time you finish those books you won't be able to afford to go onto this site.