- Everything about the Zombie Fae is creepy, especially Aki, who cheerfully spouts religious propaganda while walking off gruesome injuries.
- Martou is a confirmed poacher and has ties to Reconquista. He bought several pixies kidnapped from the Tarbes Garden. A possible horrific result is shown in an author omake in which Bidalsha stumbles upon Sheffield's experiments.
- Ephialtes and Sigurd's plans for the Fae amount to genocide and enslavement. The former's former NEET status and the later's revenge have been twisted and magnified by The Transition into unfettered madness. Their two forms of malice and scheming make them scarier than Rip Jack. Specifically, Sigurd plans to mutilate Sakuya to sooth his ego and Ephilates plans to rape both especially Leafa and Sakuya.
- Octavia's Shapeshifter Swan Song in the 3.0 Beach Episode invokes the Terminal Mutation form of the Transformation Horror subtrope. Somewhat subverted in that it ends with a Ridiculously Cute Critter.
- From the enemy's point of view, the Shiori. The chase scene where a terrified Sheffield tries to run from them reads like a horror novel.
Nightmare Fuel / Halkegenia Online