After Returning from Transmigrating into a Book, the Yandere Heroine Came Knocking

To save my gravely ill younger sister, I transmigrated into a book and agreed to the System's request: turn the obsessive female lead in this redemption story into a normal person.

[System, you mean that female lead who keeps everyone at arm's length, has an overwhelming possessive streak, and could destroy the world when she goes berserk... is this timid little girl in front of me?]

[That's right.]

[That's seriously criminal!]

[I'm not asking you to pursue her... Don't you think raising her is more exciting? If we get the chance next time, I'll switch you to a female lead who's bigger in every way, okay~~]

[...]

At last, I had raised the female lead into the person she was meant to be.

When it was time to say goodbye, her eyes were red, and she clung tightly to the hem of my clothes, refusing to let go.

I simply held her gently and told one final lie: Be good. I'm going to buy you some candy...

Then I disappeared.

The instant I returned, the System let out a piercing shriek that I couldn't hear.

[Wasn't her affection score for you 8? When did it turn sideways?!]

Months later, a girl who looked exactly like her appeared before me.

A friend leaned in and whispered, "Did you two know each other before?"

Suppressing my alarm, I denied it outright. "How could we?"

She just happened to look like her.

"Obviously! I'm not blind... When other people talk to her, she can barely be bothered to look up. But when she asks you questions, she sneaks forty-nine glances at you in three minutes."