Hmmm, I actually like this idea a lot.
Rider says he doesn't want a partner so I can't go against that, and I understand, but there's no reason why another Secret Police officer couldn't exist, or perhaps Karpa is in a different branch of the military/peacekeeping force all together. Maybe he answers direct to the emperor and disapproves of the way Rexxar occasionally works with the criminals in persuit of bigger fish. Possibly even looks down on Rexxar for being a mixed breed. A hard line "Pure-Breeder", a race cruisader who has beliefs more hard line than even the Emperor perhaps.....
A loyal soldier but a loose cannon at the same time. Believes all non-purebred animals (And especially cats) ought to be rounded up and launched to a distant moon.
Hm, this could work, but then again... I can't volunteer up spots on CT's side either.
What do you say Gray? Could you settle for being a "Dog of the Military" instead of a police dog?
I really like this idea. Especially the crusader part and being more hard line than the Emperor. The loose cannon adds a nice touch too.

