tvtropes.org/pmwiki/pmwiki.php/Haiku/NightmareFuelWhile it hasn't gone full slasher territory just yet the story still presents plenty of terrifying material.
-For starters, there's the way Noire deals with Phoebe annoying her. While the anonymity between the two had apparently stewing for a while in past encounters prior to the start of the series, the ultimate resolution of it is highly disturbing and serves as Noire's establishing character moment.
--First, there's the encounter on the bus. After ignoring Phoebe's yammering the entire time, Noire turns to leave only for Phoebe to smugly block her until Noire agrees with her mean spirited ramblings. Noire's solution to this is to outright grab her by the face, lift her up and throw her aside before leaving like she's nothing. A minor moment to be sure but it would not only get a scarier callback later but it serves as a subtle warning of Noire's more brutal and savage nature she keeps under wraps.
--Next, Phoebe, apparently not learning her lesson, pursues Noire and continues heckling her. Noire gives her clear warnings to leave her alone. Phoebe continues up to and including and grabbing her arm. At which point Noire turns right around, gives her a Death Glare, and chills the air around the hallway so quickly and suddenly she chills and numbs Phoebe's arm forcing her to back off. Noire then leaves her there as the hallway returns to normal. Phoebe is noticeably disturbed by this and even the other students were suddenly on edge when Noire started getting annoyed with Phoebe.
--Then comes the big moment. After recovering from the shock and rubbing her arm back to being warmed up, Phoebe desperately tries to calm herself down and reassure herself that she could 'cancel' her and handle Noire. She opens her locker and then a blood bomb that Noire rigged up explodes outward and showers Phoebe with pigs blood and entrails with toy spiders for flair! Literally bursting out of the locker, splattering all over the girl, her belongings, the wall, the floor and even a couple of other students! People immediately begin screaming in horror and fear while Noire finally cracks a small evil smile fully aware that she likely traumatized those girls, and potentially everyone else who witnessed it, for life. We later learn that some of the students ended up vomiting from witnessing it and had to go home.
--The fact that, despite her obviously being the culprit, there wasn't any evidence to link Noire to the crime. She was questioned by the police, they went through her locker, they checked the camera footage and there was nothing for them to work with! The fact that the principal was talked into what was essentially a Deal With The Devil with Noire for her to 'resolve' the problem with the recurring problem student Phoebe, meaning he has to keep quiet about it, and that it likely roped in others, is a scary thought.
-After a bit more time and student interactions, The School Alpha Bitch Jade gathers up a few members of her Girl Posse and they guide her into the bathroom where they attempt to interrogate Noire about what happened to Phoebe's locker and make it clear that they're willing to use force on her if necessary. They outright block the door and Jade even grabs a broom to use as a weapon. If Noire were a normal girl this would be a terrifying scene of violent bullying like you'd expect from The Cobra Brats. Instead...
--The fight is completely one-sided in Noire's favor! Despite them having the numbers advantage, Noire trivially overpowers all of them, hits them against objects in the bathroom and one girl nearly falls against the metal part of a toilet and only barely manages to save herself with her hands! The girls all get smoked sure but what happens to Jade is honestly the most brutal. While Noire is honestly and obviously holding back the beatdown still manages to be surprisingly brutal regardless.
--Jade doesn't land a hit, is quickly disarmed, gets grabbed her face and is ragdolled by Noire! Her head is thrown against the mirror, her face is smashed into the sink, she is grabbed by Noire again, her head's slammed against the side of a bathroom stall, and then she's flung to the floor while Noire kicks up the broom, grabs it, presses it against throat and flat out presses the handle against Jade's throat while giving her a clear and dire warning not to mess with her again. Fortunately she does spare Jade for now but the warnings, both physical and verbal, give a very clear example of how dangerous she is.
-A moment of more downplayed horror comes from a brief encounter with Trevor. She is seen nonchalantly walking past his fight with Maxwell and the rest of Trevor's gang. All normal right? Well...the moment Trevor tries to grab her Noire does...
something that completely wipes him out! He goes from standing and reaching out to her to completely collapsing on the ground and feeling indescribable pain and agony travel up his leg and spread throughout his body! It only lasts for a few brief moments but it completely drops a towering brute with zero effort on her part. It really builds up the sense that whatever Noire is she clearly isn't human.
-Speaking of non-humans! Noire's driver showing up wearing a fancy suit and a creepy mask and driving a Funeral Limousine is eerie, as is the music playing inside, but not too bad up until Noire and Solomon arrive back at The Nightshade Family Mansion. Once the garage door closes and locks them in from the outside world, Solomon, at Noire's reassurance and urging, removes his mask to reveal himself to be a freaking undead zombie whom Noire is not only on friendly terms with and the story shortly thereafter basically states that Noire's mother was the one who resurrected him, apparently via a form of necromancy which she has used on others.
What is with this family?