It's because his family is the strongest especially when it comes to killing monsters and demons. You know the saying "when you cut the head the body will crumble". In other words Hugo is the head and the body is the community. Him killing the wife and getting rid of the daughter caused Hugo great grief to the point it became easier to manipulate him. In turn Hugo became cold,ruthless, and feared. The grief he held turned into vengeance. The demon easily manipulated him to believe that the barbarians were at fault for kidnapping his daughter. Cause the Barbarians are strong people who also can kill demons and monsters. However, Hugo clan is a bit stronger so Hugo clan wiping them out bam don't have to worry about them anymore nor a potential alliance. Killing Vikir is because he was 1 of the strongest warriors Hugo had he was a faithful,loyal, strong, and smart warrior. So he had to also go. So taking away all of Hugo strengths will leave nothing but weakness. Which in turn was great for the demons to come back and rule. Vikir stated they demons came and conquer quickly. That's what I gathered
Why is the demon in Set so obsessed with Hugo to the point of going after his family (both mother and daughter)? I don't get why go through all the trouble to make him miserable...and also why Hugo?