Warning! MAJOR unmarked spoilers ahead!
- Everything that happens to the Go family. First the father disappears, then the mother deliberately draws the killer's attention to protect her children and gets killed, and then the older boy does the same to protect his little brother and almost gets killed too.
- The murder of Bong-yi's grandmother, and Bong-yi's reaction when she identifies the body. Especially because her final interaction with her grandmother was arguing with her, and now Bong-yi will never get to reconcile with her.
- Mu-chi is Forced to Watch as a serial killer holds his brother hostage on live TV. He begs him to stop but the killer murders Mu-won anyway.
- Ba-reum kills two of his cats when his original personality takes over. The next morning he finds the surviving kitten and apologises to it.
- Ba-reum finally regains his memories and realises he's the real killer. Cue a major Heroic BSoD.Ba-reum: It was me. It wasn't Sung Yo-han. It was me.
- As he dies Ba-reum imagines he sees his younger self asking God not to let him become a monster.Ba-reum: The Almighty heard your prayers. You're no longer a monster.
- The last lines of the series, as Mu-chi stands at Ba-reum's grave.Mu-chi: And in the end, he died in extreme pain and misery as he repented for his sins. Did the deity do that to punish him or to save him?
