- A central premise of the series is Maika's struggle with an ancient eldritch monstrosity for possession of her body. Not only that, when the Monstrum takes control it seeks out any nearby intelligent living beings to drain their life essence for sustenance. To say Maika is unhappy with this arrangement would be an understatement.
- The setting takes place in a never-ending war between the humans and daemons. As you read through the chapters, this war made the worst wars feel like an understatement.
- As much as human prejudice said Daemons are monsters, the humans had no qualms putting Daemon children to death. They are willing to send children into No-Man's Land under crossfire, use them as Guinea pigs to create weapons to make Daemons feral and kill each other.
- When Maika is interrogating Yvette Lo Lim, Yvette suddenly breaks into a very unnerving smile
◊, with sharp, bloodstained teeth. - Maika's narration as the monster drives her to kill animals and eat their hearts."When we were slaves and starving, we once ate the contents of a dead boy's stomach. We said it wasn't like eating the boy. But now I know the truth. It was."
- The Isle of Bones. It's surrounded by ghosts, warning travelers to leave. On the island, Maika finds stranded humans being slowly transformed into parts of the island, seeming to be conscious the whole time. Then the group notices they're not alone, looking behind them to see a creepy group of people have been following them the whole time.
