In the Dresden RPG, a Scion is someone who has something<em>interesting</em>in their ancestry ... half human, half something else. Given there are a few of us with familiarity with the Scion RPG, it's maybe an unfortunate term, but it might be possible to work something out along those lines. For a cat girl, perhaps an Emissary of Power, as opposed to a Scion?<br/><br/>The firebender would be a Focused Practitioner, a wizard who specialises in a particular type of magic.