Earlier I was in the stellarium on my wizard, (SLEWYN WAS A NIGHTMARE, even with prisms .... but thats beside the point) and I noticed something. The school focuses on polymorphing, right? Well, Slewyn is , yet no polymorphing. Also, the high resist and boost. How does that make sense? He's not . One other thing, he uses spells from the other schools, yet none from his. I'm just wondering whats the reasoning with this boss.
When a boss isn't a main school, it's usually just a combination of schools or to symbolize something. They have to use off school spells the majority of the time, since just polymorphing or auras won't get you anywhere.