There's irony within the fact that her name's Sarang (Love in Korean). A girl who struggles to identify with emotion the way typical people would. A girl who's probably only received a sliver of love by her mother before she died, without enough time to break the feeling down, sit with it, acknowledge and relate to it. Without the opportunity to, because the second wave of abuse by her father followed quicklier.
Even her grief for her mother and the stress from the hardship she experiences comes in bursts. She holds compassion or fear, to return the covers she took from her in the freezer, in hopes of her coming back. And anger and regret that she's not there but doesn't understand how to interpret any of that and externalise it, where to direct it. By next morning she's functional again, but remains heavily disregulated. Sometimes when she's home, it seems that she dissociates.
She's not a perfect fit for a diagnosis like psychopathy or aspd, and she's not a perfect fit for borderline personality disorder either. She introduces manic punishments only in correlation to what she's experienced at home, in memory. She's trying to understand a world that reacts on things so differently to her, but the kicker is she's been heavily exposed to abuse from a young age, and that could have impacted her cognitive development, rather than her confusion being a consequence of genetic abnormality.