You Weren't My Sister, but My Fiancée?!

Vol.2 Chapter 7.1: Extras
Vol.1 Chapter 7
Vol.2 Chapter 7.2: Special Chapter
Vol.1 Chapter 7
Vol.2 Chapter 7.2: Special Chapter
Humanity, love your little sister.I miss the time when her younger sister Kana was fond of me.Takashi Shiina lamented the current days when he was often ignored.One day, his parents cut out a shocking story.Surprisingly, he wasn't his real son... but he was his sister Kana's fiancée! ?The definitive version of Reiwa's younger sister manga!