- The car chase scene in the beginning. Hayate gets hit by the burglars' car. He comes back up well but he's bleeding and smiling happily.
- Ginka Saginomiya, Isumi's great-grandmother: To maintain her youthful appearance because her true form reveals that of an elderly woman, she has to suck people's blood to the point that they badly need a blood transfusion or else they'll die. When she asks Hayate to let her suck his blood so she can regain her youthful appearance, he happily agrees, much to Isumi's horror. Hayate comes back to the mansion and Nagi questions what happened to him. He responds that he donated some blood.
- The Tiger's Den for Butlers episode: Hayate gets stabbed by a poison arrow, and is soon afterwards given the explanation that if he walks 100 steps, he will automatically die after walking the 100th step. Try passing the butler test to redeem yourself worthy of your master/mistress's butler if you can only walk 99 steps with the step after the 99th one killing you.
- Isumi loses her powers, and Hayate goes to visit her when Nagi mentions she is "unwell". When he visits her and meets her family, her mom explain that she's the strongest member of the family and the only way she can regain them is if she sucks on the blood of a butler who has been unlucky all his life, strong but has an effeminate appearance, and has a name starting with the character "Ha" to the point that he's going to die quickly (basically Hayate).
- The beginning of Episode 10 of Season 3. Hayate gets stabbed by the Kurotsubaki and sports the blank eyes like he was actually going to die. He comes back alive and well without any visible wound nor damage to his clothes. However, he acts entirely different from his normal self. The same episode reveals that when a person gets stabbed by the Kurotsubaki, the victim's soul is swapped with the soul trapped in the sword and vice versa.
- Hayate's childhood as a whole. Think about it, since the age of 8, you have to work repeatedly to pay off your deadbeat parents' ever-expanding debt, meaning that you have to frequently skip school, thus missing necessary education. Sometimes, the parents take away those earning you've just earned and waste it off on needless spends. Must put a huge strain on you for all of this.
- Beginning around chapter 488, the entire Hakuo Academy take a trip to New Zealand. Whilst it would be normally a vacation, it's actually a survival trip where the students are sent to a hotel called "Prison", and many are quitting the trip due to how hellish it is.
- In chapter 489, Ruka implies that should Hayate's debt be paid off, his life will be over. Whether that's just simply a comment that eventually holds no weight in the next chapter, it could very well imply that someone will kill him should that happen.
Nightmare Fuel / Hayate the Combat Butler
Even for such a wacky show like Hayate the Combat Butler, the series does have its share of terrifying moments.