Nightmare Fuel / The Monstrous Duke's Adopted Daughter

• From the first chapter showing Leslie about to be thrown into a fire pit, to all the times she's abused and mistreated by the Speràdos, it's chilling to see. Plus her nightmares are a literal example, with a being of fire not only going after her, but ordering her to assassinate Duchess Salvator who treated her kindly, "for the glory of the Speràdo family."
  • The Speràdos themselves are walking nightmare fuel. Abusive noble families are nothing new in literature, but this story goes through the extra mile to show you just how cruelly Leslie was treated, effectively considered little more than an asset to inevitably be killed off once she fulfilled her purpose. Even her mother, who didn't even want to give birth to her in the first place, was in on it and emotionally abused her. And whenever the Marquis gets angry, he flips the fuck out.
  • The series also becomes rife with parental concerns because the Marquis stops at no end to try to get Leslie back from the Salvatores, including trying to burn her alive inside a carriage, trying to kidnap her from her home in her sleep in a small militia's worth of an assault on the manor, and even attempting to exploit her kindness for another person to torch the both of them to death out of spite.
• The Child Protection Act ends up being a Chekhov's Gun in the Noble's trials; what was intended to protect children ends up getting exploited by families like the Speràdos with impunity, invoking no small amount of fear when the reader realizes that regardless of how shamed the Marquis would be, he's legally "in the right" and would've taken Leslie with him to likely never be seen again had Konrad not stepped in at the very last minute. It calls to mind real family abuse cases that use the law to their advantage to get away with it. Even the Emperor, who invented the law to protect children, is briefly shocked and appalled at how his well-meaning law has been used to aid an abusive father.
• The theoretical truth of the Speràdo family: their first two generations were silver-haired like Leslie, before the third onwards were headed by blondes. Only the silver-haired contain the vast majority of darkness power, while the blondes inherited very little — to which the entire sacrificial fire pit was created to literally throw even newborn children into so that their powers could be harvested and exploited by the blonde members of the family. Even worse, the founders of the legacy were seemingly benevolent people that helped even form the modern language, so the whole hellish ordeal Leslie was born into over thirty generations later was the equivalent of a power-hungry individual marrying into the family and having their murderous greed balloon outwards with no one to stop them.