Manhwa where the main character's brother kills their family and overthrows the king

Question

I am looking for a manhwa where the female main character's "brother" kills the family and overthrows the king. She and and her brother were bullied in the family. The main character comes back as a child and is nicer to the brother. The brother still kills the family, but spares the main character. I think it's found out later on that the brother and main character aren't related.

The brother is black haired and the female is blonde.

It's a reincarnation story. The brother and the female main character are part of the royal family, so the king is their father. The brother is an illegitimate child, so he was bullied by the rest of his family. However, I think it's later found out the brother's mother also kinda forced him into it, as revenge. The manhwa isn't completed yet, but the novel it's based on is.

Answer 1

The Tyrant's Comfort Doll seems like a good fit.

From Baka-Updates:

Legend has it that a man with black hair and red eyes will bring ruin to Den Helder's royal family. Because he was born with these features, Rayton is shunned by the palace as "the cursed one." When the vengeful prince stages a bloody coup d'état years later, the powerless youngest princess, Setz, also died by his sword. Little does Setz know that she's about to wake up in her body five years in the past-- but now that she has, it's her chance to get on Rayton's good side and turn her fate around. Cracking the prince's cold exterior is a challenge, but once she does, there seems to be no going back! As Rayton grows more and more attached to her, Setz is pulled deeper into the midst of the dark conspiracies brewing around the palace. Has the princess truly escaped death, or is she in more danger than ever before?

As noted in the plot summary above, Prince Rayton was shunned by the palace due to a legend that a man with his features would bring ruin to the royal family.

He was the product of an affair between the emperor and a dancer named Liza, and when Liza was murdered by Yerna -- a concubine of the emperor -- Rayton snapped and killed the rest of his family, including the protagonist, Setz.

Setz was Yerna's daughter, and was poorly treated herself, looked down upon by the other princesses, and receiving no affection from her mother, who wanted to marry her off to a much older man.

After her death at Rayton's hands, Setz wakes up back in her own body, five years earlier, and opts to try and befriend Rayton in order to change her fate.

According to the plot summary for the novel, Setz and Rayton aren't real siblings, and I definitely get the sense that a romance is developing between them in the manhwa. The manhwa doesn't appear to have reached the point where he murders everyone (except Setz) again though.

At that moment, she stumbled and Raytan pulled her body into his arms. His red eyes started to gleam suggestively while looking down at Sezh who was trapped in his arms.

“You know we are not real siblings.”