Quick Transmigration: Help! The Yandere Villain Just Called Me Big Sis!

[Quick transmigration, 1v1, both leads' first relationship, yandere, villains, conquest System]

Si Wan died, and it happened out of nowhere. The magic power she'd had since birth was gone too, all because she curiously watched a goose bite a pig's tail for a couple of seconds. She suddenly died of a heart attack?! She'd been healthy for eighteen years. Where did a heart condition come from? Does that make any sense?!

Just as she was getting ready to meet Great-Grandma in the afterlife, a "green snake" with claws dragged her back.

Si Wan says she doesn't want to live, okay? Just as she waves to Great-Grandma again, the "green snake" cries out,

"Hold on, brother! Sign a contract with me. There are handsome men, and I'll help you get your magic back!"

Well! Si Wan quickly pulls her hand back.

Oh, it's not that she wants handsome men. It'd just be such a waste to lose her magic~

Si Wan shouts bashfully, "I'll sign!"

Later, Si Wan asks the System beside her, looking completely baffled,

"Save the villains in three thousand worlds?"

"That's right."

"There's something wrong with them, isn't there..." Si Wan cries as she looks at the villains of the worlds:

The cool transfer student holds out drugged milk tea to her: "Wanwan, drink up."

The white-haired young courtesan smiles and bites her ear.

"You're so sweet, big sister. I knew it the first time~"

The younger demon serial killer gazes at her with shining eyes and points to a wardrobe full of clothes. "Little angel, will you put these on for me?" "No? Hmm?" He smiles as he gives the iron chain on her wrist a little tug. "Sweetheart, you don't want to be punished, do you?"