If Daughter of Smoke and Bone had a villain, it would have to be Thiago. Let's make a brief checklist of his villainous traits, shall we?
We find it difficult to sympathize with Thiago, unlike Kazimir, who's a little pathetic. Sure, Thiago is a studly, furry, wolf beast, but he's no Jacob Black. This guy is egocentric and nasty. He basically represents everything that is wrong with the war between chimaera and seraphim: it's about getting what you want at any cost.
When Madrigal wonders if her people can be made to see the virtues of peace, she ponders, "'Some,' […] thinking of her comrades, friends. The White Wolf. 'Not all'" (56.78). Can Thiago be persuaded to join the side of peace? Or is violence the only answer when dealing with a man like this? We suppose we'll have to wait to find out if this guy's even in the sequel. Harumph.