Out of context is one thing.. but you completely mistranslate a word without any basis to fit your idea of a herb.
Plus the language is not so out of context in this manga.. the author uses the word 'Heldenmörder' later on. Which is basically merged from two words: 'hero' and 'murderer' and describes the killer of one of the 7 heroes. And there're other uses aswell. I'm sure HIS use of german is quite intentional and not out of context just cause it sounds cool.^^
I'm not saying his use of grammar is correct though.^^