PPsama's manga / #emotionally strong female lead(2)

Roxana : sadistic yet beautiful. She is intelligent and her goal is to survive by saving the fl’s older brother so that the fl doesn't go insane after, and also take over Agriche. Jeremy : Roxana’s half little brother. Growing up deprived of love in the Agriche, he is obsessed with roxana, the only person who has ever been nice to him. By nice i meant sadistic + sisterly love. He would do anything for her and gets jealous if anyone were to take his sister’s attention away from him Deon : roxana other half brother. Also obsessed with our lady because he want someone to have some form of feelings towards him. It can be any type of feeling as long as its genuine, and roxana is the only person who ever gave him what he wanted, even if its hatred. Deon killed roxana’s brother, Ashilly, causing her to hate him

Reincarnated as Illyana, a villainess in a novel who is going to be killed by Magnus, a royal decendent who was captured and brainwashed to become her beast. In order to avoid her death as planned in the novel, Illyana attempted to free the beast, but turned out the the original Illyana had planned everything, including her death, all along (discovered through diary). Apparently not much is known abt our villainess; how did she know the future? Why were there bruises and abused marks all over her body? What was the feeling between Magnus and the original Illyna? And why did Magnus kill the original villainess?