This is just a guess but Tegiri looks like the bounty hunter type of law enforcement, or at least trying to be - I agree with your assessment of him as a blowhard. That's why Prince of Void is the top of my classpects guess list for him; if he's actually any good he could be something else, maybe Knight, but I like the idea of him being a lousy fighter because he's destined to "destroy nothing". That would also work if he is a successful active criminal-hunter, "destroying secrecy".

Honestly I don’t really know if Alternia has ANY other type of law enforcement aside from the Bounty Hunter type.