I've been putting off this post, because I keep hoping something will come of the mountains of books I've been pouring over. I'm running out of places to look here, I'll probably move on to another library soon. Maybe somewhere else will have the information I'm looking for.
It's actually surprisingly easy to track mentions of the monster through history, if you know where to look. I was surprised to discover that I'd run into mentions in the past-the Der Ritter of German folklore. I'd never paid much mind, I was studying warfare, not folklore, so I didn't really care to look into it.
There are descriptions of children taken and people killed, as well as lots of discussion of it both in a practical, half mad Lovecraftian sort of way and in a detached scholarly manner that makes me wonder if they even knew they were writing about something real.
There are exactly no useful mentions of any instance of the monster imprisoning an adult against their will. None at all, so far as I can find. The closest I can find is this. There are some books that back up this theory, though they usually also tend to assert that the monster is a manifestation of the devil.
I've come to the conclusion (with a little help from a friend) that my best bet is to go in and try to get more information. I plan on checking out the environment thoroughly, as well as seeing if I can get any more useful information out of Sam himself.
I realize that the logical conclusion here is probably that none of this is real. But I can't give up on him until I exhaust every option. Maybe that makes me stupid, maybe that makes me gullible. But I love Sam, and I can't just let him suffer.