The risk the band took when naming themselves behind a concept. Irrespective of their personal harm, reaching across mediums to claim the name from a movie is the same as reaching to a video game. The concept of hunting demons is exponentially older than this bands formation in 2000. Hell, the Abrahamic demons they sing about aren't even in the same mythology as Korean shamanic demons. The band should not get to lay claim all these different interpretations from their name alone. This is even more egregious than Buc-ee's sueing any store with a cartoon animal logo, since at least they are both stores selling physical goods. Demon Hunter the band can't even muster that much of a claim.
Well see how this plays out. While I'm definitely not rooting for Netflix, I am decidedly rooting against cross genre, cultural and medium trade mark overreach.