The Underworld rules are available in two separate rulebooks; the 2018 Core Rulebook, which contains all of the main rules pertinent to new players, and the Soul Frag Book [2018 versions are now live!], which contains special skills that can be unlocked with Soul Frags, a type of points awarded to players who donate props and costuming or volunteer their time to Underworld.
Questions about the rules? Feel free to ask our New Player Liaisons!
For more complex and nuanced discussions of rules and mechanics, see our worldwide rules forum here.