I really don't think that Veil is an evil creature. Despite the fact that he is not part of species that are generally good, I really do think that he is good. For example, the vermin Blaggut was a corsair and yet he killed his captain for his murder of the Badgermum, he found the courage (good beast trait is it not; vermin have no backbone,as the saying goes). Sixclaw was the son of Senior Sixclaw who was made captain of his horde because of his savagery and strength and cruelty so of course it took some time for the good to soak in. He tried to save Bryony: gratitude at the very least. Another good characteristic.
Fenno, a shrew in Marlfox, out of pure spite killed Log-a-Log only for the measly reason for backing up Dippler. That really is not a good reason to kill and he did it behind his leader's back during the confusion of a charge. I sentence him of cowardice and jealousy/spite in his moral character.