>Somewhat regular looking human, has brown hair to look even more normal. Only looks strange due to the artstyle
>is actually not quite human
>orphan
>existence in the timeline is an anomaly
>has unique transformations exclusive to different routes
>is the sane one of the cast, deriving lots of comedy from reacting to other characters' eccentricities
>also has bouts of agressive behaviour due to anger issues
>has to keep in line all the crazy and/or stupid monster girls that join the party
>shows a wide variety of facial expressions, while original love interest has little to none
>love interest is secretly an angel
Kazuya is a weird guy, isn't he?
Also look at this cute picture of Sonya.