Let's try to figure out something.
I think we should try with different languages beside English: Black Dragon is Chinese, BRB is Spanish, and Dracco is German. Russia is another of large market, and I would put it in the list. My bet is the alphabet/scripts could be words of one of these languages, but I would not exclude that sometimes they could mix things keeping the same alphabet.
I don't know nothing of Chinese, so I don't think I will understand how dechiper what they wrote down if they use that. :/ Spanish and Italian are very different, although some words sounds similar, so if is Spanish I could recognise it.
We can't be sure, but we can start thinking that in the flyer is wrote "Monster". Is also possible that the word is "Wanted", "Beware", or something else, but we need to start from something.
English: I don't find a six word letter for "monster", they fall all to over or less of six (like "freak"). I think they aren't using english there. Is possible that is another word like "attention", "beware", but if the alphabet is working, mean is a word without same letters in it.
Spanish: should be "monstruo", too long. Irony is that the Italian word is very similar but of six letters, "mostro".
But there is "Bestia" (this word is same in Italian too), that mean "beast" or "dangerous animal".
German: mainly "Monster" or "Scheusal", but there are some other terms: "Untier", close to the meaning "beast, animal", a six and different letters. That is very fitting becouse in the flyer there is a "large beast".
Russian: I find монстр, monstr translittered, that is fitting too! There also other russian words that could work, Zejgar?
Chinese: 怪物, that translitterated is a six letter word could fit too, "Guàiwù"; but I find strange that the Chinese artists translittered chinese words, thinking that the "letters" of their alphabet represents entire words, for what I know.
So, for what I see, this time the English is not the language used, so I would check more other languages. There is the fact that Wranglum is, anyway, a English pun, so I still would not really take out this from the list for now.