My Little Sister Is Definitely Not a Fallen Angel

This book is also known as The Internet-Addicted Girl's Plan to Quit the Internet and My Fallen Angel Little Sister Wants to Conquer Me.

My little sister, once an outstanding angel of the Heavenly Realm, fell from grace and became a fallen angel. When I, her older brother, found out...

To keep my little sister in line, I decided to educate her with love.

All my little sister wanted to say was:

"Eat shit, Onii-chan!"

Then one day, my little sister discovered a game called My Little Sister...