She's Only Three, So What's with This Evil Supporting Character System?

(The rating was just added, so it’ll go up!) [No romance + System arrives fifteen years early]

Jin Lanyue, the adored darling of the Beiding Marquis’s household, gets bound to a System that claims she’s a vicious supporting female character

[Today is your eighteenth birthday. Everyone has turned against you, and you’ve decided to destroy them all!]

Jin Lanyue stares blankly at her chubby little hands, one of which is holding a pastry with just one bite left.

But, but she’s only three!

The clueless little girl starts following the System’s instructions to “do bad things.”

The System tells her to poison her family

Jin Lanyue chews on her finger, realizes she doesn’t recognize any of the poisons, and comes up with the bright idea of sprinkling in lots of seasonings instead.

Her mother: “Aww, my baby is so filial! She’s so little, and she’s already cooking for us herself.”

The System tells her to steal money

Jin Lanyue steals the pocket money her father set aside for her ahead of time, then buys snacks to share with everyone.

Her father: “My precious daughter is so thoughtful and generous.”

The System tells her to take the prince’s most beloved possession

Jin Lanyue has a brilliant idea and brings his puppy home to raise. When the prince angrily comes looking for her, he finds that the puppy, once all skin and bones, has turned into a big, round furball.

The prince: “I’m sorry, I misunderstood you. You’re such a good person!”

Jin Lanyue tilts her head. How come the more bad things she does, the better things turn out?

Later, when the original novel’s heroine returns reborn, full of fury and determined to crush little Jin Lanyue beneath her heel, she senses that something is off.

Original heroine: “Why is everyone on her side?!”