No, I'm not talking about him using the Job Class Ninja, but if you look at his hometown of Lix, its in a remote part of the world surrounded by mountains, which is only accessible through Airship (which don't exist anymore) and Black Chocobo (which is a rare species of chocobo) and the town sells Ninja Suits, shurikens, and Skeans exclusively. Could Batrz be from a long line of former Ninjas?