As a person who has not read the novel, but I did read some spoilers that the novel has not yet finished. Now so I have to create multiple setting of "what if" - 1The mother is like that because she lost herself or is a witch. 2alguin offers something to Varkas in exchange to bring Thalia to life or go back in time. 3 The twins and the kingdom fall. 4.- I leave it to my imagination. (=・ω・=)
Since we're all ranting:
I also think the second empress is the single most detestable POS. She raised her daughter to feel some love and promptly dropped her like a banana peel thinking she would pivot into an authoritative wench on her own. Words cannot describe how much I hate this woman and knowing there are real woman in history just like this. The emperor is so passive in all this but he doesn't get a pass; I'll just channel all his faults onto her because he couldn't keep it in his pants.
If I met Thalia in real life without knowing her backstory, I would hate her. But she didn't stand a chance with a mom like that. It seems from the first time she met her half siblings, they hated her because they couldn't punish her mother and the servants encouraged it.
I also can't hate Varkas because he was basically a prisoner in a war camp, driven to hide himself. There's no question as to why he is so fond of his horse. He knows what each of the imperial siblings are capable of. On a subconscious level, I think he knows Thalia is the easiest to get along with (except the youngest one.) It's obvious she has to fight for every inch she can get while the twins have respect given to them so they hide their bad side except when it comes to her.
To briefly mention the younger prince, I just feel so bad for Thalia having to see what she could have had; she's right that his birth has made her useless because she was just a pawn for her mother to win favor. And she's right to push him away because he hasn't been given the same message to fight for respect and power, which he unfortunately needs to learn because he's the next target after Thalia's gone. If the second empress thinks she can pave the way for her son to rule, she's got a long, hard struggle ahead of her. Though Thalia is right that her mother was afraid of what she would do to her brother so they haven't met since he was pretty much born, she wouldn't have it in her to harm a baby, someone else who has done nothing wrong; the second empress shouldn't be afraid of the habits she forced her daughter to adopt.
And to the twins, they can f-ck all the way off. They misplaced their own anger, whether they were taught to or not. They never gave their half sister a chance. The crown prince especially shouldn't rule a country because he already believes he and his sister are gifts from God (by the way he thinks Varkas should be grateful for being his "other half's" fiance.) Ayla hasn't been shown much but she is not a passive participant in her half sister's abuse. I could let her slide if she hadn't thrown an immediate temper tantrum/anxiety attack over just seeing her half sister for what seems to be the first time outside of the funeral. We don't know if she deserved being poisoned but I say her twin sure as sh*t does so until we see more, I am going to assume that she does. She's patiently feeding Varkas her love my *ss; your brother alone makes any man not want to end up with you.
I had to take breaks reading this and seeing the spoilers in these threads, it's going to be a misery slog. I better have my fluff reading on standby because I am too enraged on Thalia's behalf not to see if anyone gets what's coming to them.
Yeah, I tacked him on the end of the second empress rant because he's been so passive in the story so his biggest crime is not keeping it in his pants. But by taking no action, he as perpetuated his children fighting each other. Maybe he finds it entertaining. We don't know and we may never know because it's not about him.

SPOILERS!!!
I needed to know myself where this is headed towards since I’m pretty sensitive when it comes to these types of stories (especially if it has no happy ending). So far from what I could find (info wise) this is gonna have no Happy Ending.
Thalia is gonna die (maybe they’ll change it but I doubt it) she’s gonna die thinking she’s unloved and will never get closure.
Varkas will only start to realize that something is missing after Thalias death, he’s in denial of her death and will cling to her.
Honestly everyone is bad in the story there isn’t any good character (so far I could see) everyone is guilty.
If there’s one person I would put my whole hatred towards is Thalias mom (honestly what a pos) not even batting an eye even when she died istg I haven’t met such an unlikable character in so long I’m about to explode.
I do hope we get a redemption of sorts, maybe Varkas rewinds time (only he gets to keep his memory) I would really wanna see him realizing what she’s been going through with a heart.
Yet I can’t blame him as he also grew up without love and not knowing what love is… GOSH I HATE THIS SM ok bye