My personal biggest pet peeve regarding analyses of Belos (obviously aside from “he’s just evil and analyzing him at all means you support his actions” and “he deserves redemption actually”) is that so many people take his hatred of witches completely at face value--as simply being the result of his indoctrination into witch-hunting as a child in Gravesfield, that these are just the beliefs he was raised with and that he never grew to see past his prejudice like Caleb did. But that is such an oversimplification of his character, and it also ignores what is in my opinion the main driving force behind all of his actions: Caleb himself.

Belos doesn’t think all witches are evil because he was raised to be a witch-hunter. He HAS to keep himself convinced that they are, because if the witches are not evil, then he has two realities to face: 

Caleb left him of his own free will, not because he was under a spell or led astray by the devil.

Belos murdered his own brother, the only person he ever loved, for nothing.

And these CANNOT be true.

Belos’s need to be the hero who saves humanity from witches is not the reason he killed his brother, it’s the result of it.