Another mangaka makes a fundamental error; you complete the events leading up to the main story in the FIRST chapter. Everything prior to the main story events are chapter 0, and a waste of newcomers' time who want to know what the series is about.
It had me going at the "She's always wanted everything I had", making it seem like it was the stereotypical "green-eyed little sister".
But nope, it was me, Super Siscon!
Great subversion, author.