Yeep.
- Well, Katon Release as the name suggests involves the manipulation of fire or heat (maybe even some form of explosion). It is primarily used for offensive purposes.
- Fire is weak to Water, while strong against Wind.
- Characters who use Katon in Naruto are..anyone part of the Uchiha clan e.g. Sasuke, Itachi, etc, Kakuzu, Asuma, Hiruzen and Kakashi (that's all I can think of atm).