- The sheer amount of times Harry slips in and out of his psychopath side is incredibly disturbing to him and everyone around him (including the readers). Worst of all Bob said the influence will only grow over time and while he might not succumb to it yet, a few years could do a number to him until he makes Lloyd Slate look like a schoolyard bully.
- His psychopath side itself. It's scary to watch him slip into possessive, primitive desires for people he cares about, especially when before becoming the Winter Knight he wouldn't have thought twice about the things that set him off. And Molly, when she's close and accidentally triggers his anger, feels all of it, and knows what he wants to do. And worse, part of her still wants him badly enough that she’s willing to let him do whatever the Mantle prompts to her.
- Consider also the way Maeve (presumably under the thrall of her own mantle) played with Harry-as-Winter-Knight, as well as Slade before him... and consider that Molly now bears that mantle, has the mental mojo to feel Harry tripping along the edge, and, worst of all, her own unrequited love for him.
- There's an incredibly chilling moment where it's mentioned in an aside who some of the previous Winter Knights were - Namely, Gilles de Rais, Andrei Chikatilo, John Haigh, and Fritz Haarmann. A.k.a., four particularly infamous Serial Killers, three of whom are also generally considered to have been pedophiles.
- Not as horrifying on an apocalyptic scale as most of the below-mentioned stuff is, but early on in the book Dresden shatters a fey lord into pieces. Which given the statement he was making is pretty awesome. But then he starts dancing with Mab as the pieces crunch under his feet. Harry dances with his queen on the crunching frozen gore of their enemies. There are supervillains who would draw the line at that.
- The terrifying reveal of what exactly is underneath Demonreach. The whole island was created and enchanted by the original Merlin, using magic so powerful that even Bob doesn't understand how it works. The kicker? All of that power was necessary because the island is a prison for Eldritch Abominations so powerful that it has 6 Naagloshii in minimum security. The inmates are so powerful that the tiny amount of power leakage from all of the beings in the prison - in essence, their body heat - is the basis of the massive ley line of dark energy that runs beneath the island. If they ever get out, the world would end. Don't worry, though. They'll never get out because if the enchantments on the prison fail, it triggers the fail-safe mechanism that will kill the majority of them and slow the survivors down long enough for reinforcements to arrive and get inevitably slaughtered. Oh, and that aforementioned fail-safe is an explosion that will take out most of North America.
- Just to cap it off, try imagining what life must've been like for normal people before Merlin locked all those abominations away.
- Oh, and there's at least one other way they can get out: As the Warden, Harry has the authority to release them.
- While He Who Walks Before (a.k.a. Sharkface) doesn't have nearly the same Nightmare Fuel quotient as He Who Walks Behind, he's still a creepy mofo. He's a tall, skeletal humanoid with a prehensile cloak, scars where his eyes should be, and a ridge of solid bone instead of teeth, and he's constantly drooling black saliva and has a seriously nasty psychic punch.
- It's still creepy as hell when you think about what his Name means. He Who Walks Behind, was always behind Harry, getting closer, and closer, and closer. With a guess He Who Walks Before starts out beside you and walks further and further ahead, no matter how fast you run, you'll never be in time to save anyone because he's one step ahead of you. Either this is another advantage of Harry being a Starborn, with power over Outsiders, or he just didn't build up enough "distance" to render the situation entirely without hope.
- True to his kind, his first appearance is Fridge Horror. Just imagine sitting in a bar and a freaking Eldritch Abomination comes in and threatens one of your fellow patrons. That's the stuff of nightmares.
- More Fridge Horror. The Outsiders are under no laws like the White Council, no restrictions like angelic beings or fae (unless not being able to manifest in full power) and cannot be bound. And then they come after a specific individual...
- Titania's arrival in the Montrose Point Bird Sanctuary after Harry summons her to get information on "the contagion" (a.k.a. Nemesis). Not only does she first manifest as a tornado touching down, but she lifts Harry up by his neck and rants about how she wants to inflict upon him such horrific torments that they would make "Lloyd Slate's fate seem kind by comparison."
- The reveal of Nemesis. A sentient mental "disease" that subverts people to the cause of the Outsiders. Said to be responsible for most of Harry's major cases, and also corrupted the athame that was given to the Leanansidhe at Bianca's masquerade party, causing her to be infected, which in turn infected a Faerie Queen. What's worse? There's no way to tell who's been infected, unless you confront them. If they're not infected, you look like you're crazy. If they are infected, they either kill you or infect you.
- Mother Winter after Harry becomes desperate enough to summon her. Instead of her being summoned to Earth by the wizard, she grabs Harry by his face and pulls him through his gravesite into the farthest reaches of Faerie, where he's pinned to the earth by her sheer willpower and trapped in absolute darkness. The only light being given off is from the sparks coming off her cleaver as she sharpens it, and Mother Winter then rasps to Harry how "I have a stew to make, and I will fill it with your arrogant mortal meat." The only thing that makes the whole scene even creepier is how during this, Mother Winter's cleaver is described as being made of steel (the Kryptonite Factor of The Fair Folk)... and the steel is visibly tarnishing under her very touch.Mother Winter: Ahhh, I like nice clean edges to my meat, manling. Time for dinner.
- In the cottage shared by the Queen Mothers, Harry accidentally knocks over a jar, cracking it, and sees that the other jars in the vicinity include the black plague and countless other deadly diseases. The one he cracked? Wormwood.
- What makes it even scarier in hindsight? Those plagues were created by Mother Summer, who shows them the exact same tender attention which one might show to puppies or grandchildren. In all her (brief) appearances, Mother Summer seemed like a single truly good faerie in entire series. It is very easy to forget that she is just as powerful and utterly inhuman as Mother Winter.
- After his dismal failure at summoning Mother Winter, Mother Summer shows Harry the Outer Gates. It's the literal border of reality where The Fair Folk wage a Forever War against the Outsiders, and is described as looking like the Western Front of World War I cranked up to eleven. Suffice to say, what shortly follows Harry's full realization of what's at stake are easily the four most haunting words in the entire series.Harry's Narration: My senses and mind alike simply could not process everything I was seeing. But my heart was beating very swiftly, and frozen fear had touched my heart like Mab's fingers.
The Outsiders wanted in.- The sheer scale of it all is what makes it truly horrifying on an existential level. As Harry looks around the battlefield, he realizes that the layers and mounds of shale making up the battlefield aren't actually shale, but bones. Fossilized bones. Or, as he puts it, "millions and millions and millions of fucktons of bones." That is how many who have fallen in service to defending the Outer Gates from the Outsiders.
- The timescale is also horrifying. This battle has always waged since the beginning of time. Only, time at the Outer Gates seems to pass much faster than in the mortal world. So for every few hours of fighting, dying, falling back and losing ground that the defenders of the Gates make it through, the mortal world only gets a few extra seconds of existence.note
- Nemesis "assuming direct control" over Cat Sith. As in, Nemesis turns a violently spasming Sith into a completely still Empty Shell through Mind Rape so as to have a Meat Puppet to kill Harry with. In particular, the description of the "smug, contemptuous self-assurance" in Sith's eyes being just gone is utterly chilling along with how "Not-Sith" turns Sith's head towards Harry in a graceless manner while speaking in a voice "completely devoid of anything like personality."Not-Sith: A pity. I would have been more useful to them as an active, covert asset.
Harry: Like Mab wouldn't have figured it out. Like she did when you infected Lea.
Not-Sith: Further conversation is not useful to our design. (jumps at Harry) - Nemesis corrupting Maeve's special veil which she covers Harry with, which turns all of his verbal peace offerings to Lily into threats, insults and taunts. And you won't know it unless you are looking for it. Excellent Paranoia Fuel and explaining how she managed to convert Lily to her side willingly.
- And here's a healthy dose of Fridge Horror; what if that power was zero Maeve, and fully Nemesis? It could put conflict between almost anyone.
- And in a mix of both this trope and Tear Jerker, this scene has Lily finally flipping out and nearly killing Dresden. After going on a furious "The Reason You Suck" Speech pointing out how Harry is (indirectly) responsible for saddling her with the Mantle of the Summer Lady, she basically hurls a miniature sun at him that conjures a column of fire thirty feet high with the width of a telephone pole where it lands. Literally the only reason Harry survived was that Fix was able to deflect the "mini-sun" from hitting Harry at the last second.
- The sheer Mood Whiplash when Maeve pulls out a gun and shoots Lily, who just wanted to do the right thing, and with it, taking Sarissa away from Mab.
- Then Murphy shoots Maeve dead on Mab's indication. Yeah, Nemesis literally forced Mab to kill her own daughter by proxy to save the world.
- Making it worse is that without all the supernatural trappings, a crazed gunman scenario like this is actually quite the viable scenario in real life.
