Building a deep and characterful world, this setting is full of life. The mechanic to translate magic is intriguing and will allow a lot of character development.
I particularly enjoyed the back-story and world building aspects in Historia Rodentia. The world is rich, and ready for creating new stories and legends!
The link between the RPG and tabletop miniatures game (Brushfire) adds additional depth to the entire experience, with lots of cross pollination between the two. Both are stand alone books, but work well together to make a more cohesive setting and game experience.