Strong-Willed

Strong-Willed is a role modifier; it usually means that the player's abilities cannot be redirected or Roleblocked. Any result that may be attained can still be tampered with by things like Framer, however. In short, it greatly increases the chance of the player's ability working like the player wants it to.

Some moderators will ambiguously use this to mean that the strong-willed player cannot be recruited (by Cult, Neighborizer, and so forth). If you are not sure, ask the moderator what they mean.

Strong-Willed is not to be confused with Strongman.

Use and Power

Strong-Willed is usually incorporated for thematic purposes, or to specifically counter a particular role (like Strongman). However, in practice it does not make a very large difference.