Nightmare Fuel / Flawed

• Celestine getting her sixth brand. During the process she was slowly running out of anesthesia and the guards were refusing to give her the last brand, so Crevan took the iron himself and branded her spine while denouncing her as "flawed to the bone". Despite staying calm for the rest of the ordeal, this was what finally broke Celestine, and the scene is so disturbing that it disgusts everyone who witnessed it. What makes it so horrifying is perhaps the fact that it's Crevan, who at this point came off like a decent person with insane beliefs, and who she was once close friends with. His utter hatred of her made the scene chilling.
• A birthday party invitation turned out to be a kidnapping scheme. Celestine was blindfolded and shoved in a car, where she spent the night being driven around in circles, tortured with cigarette butts and smoke, and mercilessly taunted. They finally dropped her off at a shed where they stripped her and examined her like she was some freak-show attraction, only to then abandon her there minutes before her curfew. It's one of the darkest scenes in the book, and Celestine's fear and pain can come off as contagious.
• Celestine is at her grandfather's house trying to enjoy a birthday cake when the whistleblowers show up. The scene immediately takes a turn for the dark, as she's desperate for a place to hide and knows that if she gets caught, she and everyone else on the farm are in potentially-fatal amounts of trouble. Then, Mary May attempted to force Celestine's grandfather to burn her alive, in a fire pit, for several hours. Celestine was alive but had to watch the entire scene, and her grandfather genuinely thought he'd murdered her.
• The hospital scene. Celestine wakes up after being drugged and can barely move. She manages to get into a wheelchair and tries to get help, but comes across the kidnapped Mr. Berry, Pia, Natasha, Gavin, Logan, and Colleen, all drugged to the point of being utterly zombified. Two whistleblowers walk by and start mocking the frozen characters, showing an utter lack of empathy for the people being tortured by the guild. Celestine herself is horrified, even feeling bad for the kids who tormented her a month earlier.
• Late in the second book, all the Flawed are forced to strip down, wear revealing clothing, and be paraded through the streets while people jeer them. This, along with Crevan's "Reduction of the Flawed" plan, which is basically segregating the Flawed into ghettoes, paints some unsettling parallels to The Holocaust, and it's easy to imagine what could eventually happen if things never changed.