Kawaii Kawaii Kanojo ga Irukara, Oneechan wa Akiramemashou?

is a Japanese light novel series written by Tsukasa Kouzuki, with illustrations by Rouka. The series began publication on December 10, 2021 by ASCII Media Works under their Dengeki Bunko publishing imprint.

Synopsis
Confession of love to classmates. But that person was her sister. I noticed the accidental explosion, but it was too late, and her younger sister, who was hugging her arm, said, "Sister, I'm going out with this person!" ??