Demons and Demon Hunters Duel

A previously rather unsuccessful, barely noticed writer from Fulda has been publishing cheap books about occult finds and paranormal occurrences here in Fulda for years. He is mostly perceived and laughed at as a deranged, strange type. Until he suddenly publishes a work that unexpectedly sparks great interest and even becomes a bestseller. This work has something to it! You have to read it! ...The author was supposed to give a reading at the Vonderau Museum two days ago, but he doesn't show up. Since then, there's been no trace of him. What happened?! You have been tasked with investigating this and gain access to his studio. Can you figure out what's going on here? It quickly becomes clear, - you're not the first ones wanting to find the solution to the puzzle! Are YOU perhaps strong enough and can resist?