I liked the bit about the werewolf being the Leviathan's worst enemy. It started me thinking about evolution and primaeval times and happy werewolves chomping on Leviathans until the Leviathans were put on the Endangered Species list.
Me too, in the back of my head, anyway. I like it when a backstory is inserted that gives you a lot to think about, for one thing because it's an efficient way to squeeze as much good story as possible into a small space. A short reference to an intriguing backstory opens the story up, making the scale of it larger, without any further expense, trouble, or production time. Of course, here, I think it was sort of accidental. When we think about the werewolf/Leviathan backstory, we're making up for writing flaws with our own imaginations. Then again, that could have been a better stretch of story at that point; I'm often surprised that certain bits are better than I remembered.