Are there any novels with Evil Beastkin or Dwarves? In most Japanese novels that I've read, the race that's evil is usually, Humans (Usually just 1 kingdom or the Church), Demons, Gods, or some secret organization, I honestly can't think of a single instance where a beastkin or Dwarf has been evil and not had some kind of redemption. Plenty of Evil Humans, Elves, Demons, Mermaids, Faries, and other fantasy races come to mind, but I haven't seen a single Evil Beastkin or Dwarf. As long as they're evil enough to murder someone (Mugging someone to get money for food is illegal, but not evil), and they're not just a grunt to the real evil guy, then it's fair game.
Black Summoner (dwarf working behind the scenes, helping to start a war, have only read the manga and i don't know if there is any reason for this or not. But thus is the closest and only thing i can think of right now, fitting your criteria)
If I'm not mistaken in the name of the novel Dungeon Seeker have Spoiler Cannibal elves... I'm not sure about the dwarves. But if we're talking about this novel, they're probably evil too.
Humans, Demons and Gods can be evil, but it's hard to find any Beast-girl trope as evil in JP novels. Their love for their catgirls runs strong.