The Villain's Younger Sister

Nie AnAn woke up one day and realized that she had transmigrated as the villain's adoptive sister.
In the novel, the villain conquered left and right, and his eccentric younger sister was always close by. The two of them were rightfully the grim reapers in the book.
The very next day after her transmigration, the maladjusted Nie AnAn passed out from seeing blood.
And so -
The competitors noticed that their nemesis's sister had turned from an ugly duckling to a swan - and wanted her favor;
The original male lead noticed that young Miss Nie, who had long been chasing after him, wouldn't even give him the time of day anymore - and felt robbed;
Young Master Nie was very happy that he found his lost sister- she was so GD cute;
A certain cold and violent villain started playing hooky, and began going home earlier and earlier, and the way he talked was becoming gentler and gentler.
Villain Brother: AnAn, come here. Let me try some of it.
Nie AnAn: Hold on. It's not ready yet.