Back in my day we'd call him a gent. Since around 8 months ago, we call him a "simp".
Seriously, why did it become such a trending word? The whole Belle Delphine thing was last year, no? Dates don't match up.
@Triparadox It's a bit hard to classify. Essentially it's a comedy (some romance too, I'd say). The "dark theme" is just one of the joke. The dude is probably interested in anatomy or stuff like that (or history of serial killers, whatever. One of those hobbies that's "out there", but not really an issue) AND is a Chuuni. And as a Chuuni, he feels like he's a born killer who can't contain his bloodlust.