Arbitrary Skepticism: Pellinore. Anthropophagi? Fine. Weird worms that grant nigh-upon immortality? Boring. But the wendigo? Never in a million years!
It gets worse when Pellinore describes the magnificarum and it comes off sounding like a campfire story. No one knows what it looks like or how it behaves, yet he unquestionably accepts its existence as fact. Mind, that this is a creature whose saliva will drastically and horrifically alter the body and mind of anyone it comes into contact with, while one book earlier, he declares that the idea of a creature that can produce symptoms similar to wendigo possession in its victims spits in the face of everything be believes in.
Autocannibalism: The magnificum found in the third book resorted to this when it could no longer find food.
He Who Fights Monsters: Dr. Kearns is arguably even more disturbing than the Anthropophagi. Pellinore has hints of this, as he doesn't seem to care if people die so long as he can study monsters.
Chanler literally becomes this after a Wendigo encounter.
Will (Narrating): Gently he pulled my hands into his. His warm lips touched my knuckles. He blew onto my dead flesh. He vigorously rubbed my naked hand between his. Feeling began to return, and with it a measure of pain, the proof of life. He crossed my hands over my chest and pushed his body against mine, wrapping his long arms around me. I felt the delicious warmth of his breath against my neck."
Humans Are Bastards: The NY police beat up a hallucinating and wounded child to try to make him lie and rat out his only family figure as a murderer.
Jerk Ass Woobie: Concerning his distant father, Dr. Pellinore can fall into this from time to time.
Literary Agent Hypothesis: Rick Yancey is only the editor/publisher. The follios were actually written by Will Henry and Yancey is reading them in the hopes of learning the truth about the man who left them behind.
Maybe Magic, Maybe Mundane: Despite the fact that monsters are real, Pellinore refuses to believe that supernatural monsters exist. So, Anthropophagi are real but vampires are not. What.
I reached across the space that separated us - no further than a foot and wider than the universe - and gathered the monstrumologist's hand into mine.
Shout-Out: Several references to the works of William Shakespeare, Kearns also being named Richard Cory (the name of an Edwin Arlington Robinson poem about a rich man with a good life who shoots himself), and one remark regarding "that ill-fated expedition to Sumatra" that could be a reference to a Noodle Incident from Sherlock Holmes
Stages of Monster Grief: Chanler goes through a few of them, as he initially refused to eat (since he could only eat people as a Wendigo), but later embraced it.
John Kearns: Go on. Pull the bloody trigger, you insufferably melodramatic, semi-suicidal, blubbering bugger. Do you honestly think I care if I live or die? But you may wish to include in your calculations the fact that our work is not finished. She is still out there somewhere in the dark, and not very far, I would guess. That said sir, I would not presume to pass judgement upon the passage of your judgement. Fire at will,sir, and I shall die as I lived, with no regret.
Pellinore gives one of these to Will during The Curse Of The Wendigo.
Pellinore: You disgust me! Only the intelligent can afford to be so judgemental. Who are you to question my decisions? You thickheaded sycophantic piece of snot. I've dissected worms with larger brains than yours! You've been nothing but a burden to me, an albatross around my neck... God damn your parents for dying and foisting your despicable carcass upon me. 'It's all right sir! I'll make the fire now, sir'. You make me sick. Everything about you is repulsive, you nauseating, worthless mealymouthed half-wit."
Through The Eyesof Madness: How Pellinore tries to debunk van Helrung's argument about magical monsters since the only real witness could have been hallucinating.