The Villainous Family Loves Me Too Much!

I’ve been reincarnated as the younger sister of the male lead in the brutal sad ending novel, ‘The Saintess of the Dawn.’
The picture-perfect, affectionate older brother, the Crown Prince.
I did everything to protect my brother… but just before the happy ending, he was mu*dered.
And that was by the so-called kind heroine and the gentle sub-male lead!
Furthermore, shamelessly, the two of them accused me of being the mu*derer,
And before I knew it, I had become a notorious villainess, committing crazy deeds out of jealousy between my brother and the supposed heroine.
***
“Give me the princess.”
Instead of facing execution, I was sold off to Felosite, the villainous Archduke in the original story, to marry. Infamous for his cruelty, he was the mastermind behind the sad ending that wiped out the protagonists and brought ruin to the Empire.
But why would he want me as his bride?!
A plaything for torture?
A means to form an alliance with the imperial family?
A sacrifice for dark magic?
Or…
“Feel comfortable, Lucian… that’s what you can call me.”
“Yes?”
“I’ll give you everything you want. Just tell me what you desire.”
The sight of my husband acting shyly in front of me and showering me with gifts was unbelievably awkward.
That wasn’t all.
“Our precious niece! Let’s go building shopping together!”
“Dear sister! I brought the delicious strawberry cake you mentioned! Let’s eat it together!”
“We don’t need that distant grandson! We’d rather have our adorable granddaughter-in-law play with this old man!”
The intimidating villainous in-laws who I thought were, turn out to adore only me, sidelining their own son?!
Um… Excuse me, aren’t you villains? Why on earth are you doing this to me?”