- The Hayasaka twins' backstory is fairly disturbing. It involves a woman who kidnapped them, and kept them hidden until she died of starvation, leaving them to die alone with a rotting corpse. Yeesh!
- The Homunculi, even the humanoid ones, all have scary, warped faces at one point.
- The Karneval type Homunculi, which resemble white bipedal, multi-eyed monstrosities instead of actual humans.
Nightmare Fuel / Busou Renkin