Hmm, I'd say something like.....
Bears - sturdy, resilient, strong, can do some damage (think of a mama bear protecting her cubs). Seems like something a Defias might want to bring along as a steadfast, reliable, and dangerous companion. The dark colors would probably complement your character well:


Hawk/Carrion birds - intelligent, deadly, swift, have a menacing appearance. While parrots are in the Deadmines and would seem to suit a pirate well, I just feel they are a bit too showy and "pretty" for a Defias-turned-Alliance hunter. He may be on our side now, but he looks a bit tougher than your average Alliance soldier. As such, I think a hawk or carrion bird would be more up his alley, in the classic Defias red and/or black:


Foxes - cunning, agile, alert. They may not look quite as deadly as the other animals above, but they look like they have many of the traits their potential Defias/Alliance master does. They have sharp ears and could keep you aware of any dangers around you. They are also quick and able predators in the wild, and their abilities could serve you well. Again, black and red would look nice with you (especially black, IMO):

Hyenas - resourceful, aggressive, used to pack-hunting. These look every bit the part of the Defias hunter's go-to-hunting companion. They are accustomed to hunting in groups, but are also not above scavenging. They could make the best of whatever situation they're in, and their powerful bites are a force to be reckoned with. Many a lion has been made the whipping boy of a pack of aggressive hyenas. What hunter wouldn't want one of these fierce creatures beside him in battle?


Scorpions/Spiders - venomous, terrifying, adaptable. We all know that many people are naturally afraid of scorpions and spiders. Why not terrify your enemy further with a giant-sized version? When I think of Defias, poison often goes along with that. Scorpions and spiders both have species capable of severely damaging or even killing a human being with their highly-toxic venom. These are creatures that often make shadowy corners their home, and surprise you when you least expect them to (just like Defias!). There are several colors of both that have a noticeably deadly look to them:






Hope you find something you like out of everyone's suggestions. Have fun and let us know how it goes!