These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Nightmare Fuel: The destruction of the House Volfrieds, and Trent's backstory.
The Scrappy: The annoying girl that they save from an evil magician. Even within the book, she is treated with a polite indifference at best by the nicest character and disliked or even hated by everyone else. All she does is pander to the sole human male present and when she is killed at last, no one mourns her death.
Squick: The portion early in the book when one of the maids is described as possibly being killed by a sword. A sword thrust into her...personal area. And she was left on Lyra's bed.
The Woobie: Lyra narrowly escaped the destruction of her House, and only has Sadrao for family. As said above, Trent had one seriously messed-up childhood, and is the product of the most evil wizard known to man abducting someone and raping her, which makes some people hate him just for existing. Not that he doesn't feel incredible guilt over things he's done in his past—wait a minute...