The picture in my mind of Sylph is that they believe the most important thing one can do is help others selflessly, even if that means getting themself hurt. They like to challenge authority, traditions, and structure--especially when they feel like those things are impeding the quality of life of others. Outside of their closely-held values, however, Sylph is otherwise casual and good-humored. They like to get into troublesome situations for fun, like pranks or exploring places that they definitely aren't supposed to be in. I'd probably place them at Chaotic Good (bordering on Chaotic Stupid, depending on the situation).