I suppose Bessarion could be seen as a "bad guy".
Evil? Perhaps. Morality is a very esoteric topic, so nuanced that no one could really be the true arbiter of all that is moral or immoral (... if you believe in a singular, omnipotent higher power, who crafts humanity in their image... one has to raise the question, is such a deity a sociopath? If such a condition is almost certainly entirely born from genetics, then we have our conclusive answer there).
I've discussed before in another thread on how I visualize morality as a complex Venn Diagram; every single person alive is a individual circle within the diagram, with overlaps representing commonality of morals. Perhaps where the circles
don't overlap is where a differing of opinions is and where we see the lack of objectivity of human morality.
I've spent a lot of my free time studying the
Dark Triad, and the empathetically challenged in general, as a means of understanding how "evil" works within our own reality and perhaps to even better understand myself.
When it comes to making characters, I like to incorporate significant character flaws into how I conceptualize them. Some might think of me as a edgy contrarian, but honestly I think it makes for better characters with greater potential for positive character development over the course of a campaign. If your character is Mister Wholesome-Goody Two Shoes, and ends the campaign as Mister Wholesome-Goody Two Shoes, you likely didn't have much positive alteration of character over the course of the campaign. I suppose such a character could have
negative character development instead... what happens to them that taints the goodness within them. I'd imagine most people wouldn't like to see good people turn bad though, but ymmv.
I think, overall, Bessarion has characteristics that would put him at odds with the game world. In some ways, he wants to uphold the more conservative beliefs of the now dated traditional Faun culture, but likely simultaneously is at least somewhat cognizant of the larger society he is at odds with. He has personality flaws, some of which are perhaps inherent to the Faun species, that he must deal with and perhaps overcome.
Overall, I'd think it'd be more accurate to label him as a "anti-hero" rather than outright "evil bad guy".