Gitei wo Shiitagete Korosareru Unmei no Akuyaku Reijou wa Nazeka Kare ni Dekiai Sareru

Meltia is reincarnated into the world of an otome game she never finished playing in her previous life.
In the game, she is a villainess who bullies her stepbrother Roy, lives a life of debauchery, and ultimately meets a brutal death at his hands.
She wants to escape this environment—but if she disappears, Roy will instead be abused by those around him and eventually killed.
And besides, Roy was her favorite character in her past life. More than anything, she can’t bear to let an innocent child be driven into misery.
So Meltia makes a decision: she will play the role of the cruel villainess, shielding Roy by becoming the sole target of hatred, ensuring he suffers no worse treatment.
But as she does, Roy’s attitude toward Meltia begins to change…
A hard-mode, reverse doting fantasy where cruelty turns into love—now finally adapted into a comic!
https://www.alphapolis.co.jp/manga/official/847000614