Just a quick character sketch. Not a werewolf. The werewolves (and the humans in the same country) call his kind trollocks. The main difference when it comes to shapechanging magic is that werewolves can change between wolf-like and human-like shape, while trollocks have wilder magic that lets at least some of them turn into huge monsters.
This occasionally comes in handy for Sidney, namely if some thug needs to be thrown out of his bar/inn-thingy.