The Twilight War (Broken Sky, #1)

by Chris Wooding

[wyvernfriend]

In a pseudo-japan Ryushi and his siter Kia have spent their whole lives hidden, learning martial arts and trying to control the stones they got when they were young. They are quite powerful and there are secrets in their life but things change when their father comes home after going to the city. Imperial forces attack their home and they have to go on the run.

It's a pretty typical anime-style story with fantastic powers and a concrete evil. Quite readable.