I really like this weapon, and the twists mean it can be integrated into your campaign and gives it potential for great story telling.
If your gaming system has a way of compelling PCs to act in a certain way, it would be great to have biter slowly transform its wielder as it becomes hungry.
I really see it as a quiet parasite, slowly chnaging the behaviour of its owner to further the axe's purpose, in the same way as Toxoplasma gondii makes rodents seek cat pheromone, Biter would make the owner pick fights with the races that Biter likes.
It could be really fun to GM, with a few "You know, this guy is really getting on your nerves, and you have no idea why..." dropped every so often.
This looks very cool, I would pack all thirty into one submission and look at responses. I can not tell you if its too much if I do not see them all together. However, in my opinion, as long as a sub is good, it is not too large. My two cents.