I had a little something written where a werewolf was helping the demon Lenwick is hunting, but things go south fast. It would only take a few small changes to make the werewolf be Fenrir III. But I don't know how Pie wants interactions between the different monsters. But the rough idea was Lenwick and another hunter w/ an apprentice (not one of your characters) were hunting a demon, trap it, but the hellbeast with them turns out to be a werewolf or Fenrir III so the circle didn't bind it. Breaks the circle, demon gets out, apprentice dies, knight runs, maybe your guys stumble upon it as it's feeding or run into it as it catches him? Or something? Idk, maybe not have it be the same beast, could just be in a similar area.