Ryuki was thinking of something. It's the start of high school, which means it's the start of a game Ryuki had played in his last life.
The game's protagonist was Takeru Yuta, and the first heroine was Takeru Asuka.
Ryuki doesn't know the exact reason, but it seems Asuka doesn't love her brother as much as she did in the game.
Should I also try to add a harem?
Ryuki thought. He was waiting for his sixteenth birthday. Since he was sixteen years old, he was considered an adult, just like an 18-year-old on earth.
Now that he was sixteen years old, Ryuki decided to start his harem. He didn't thought about it, but he wanted to make his sister Saki and mother Fumiko his women as well.
Moreover, he also wanted Asuka and her mother Machiko in his harem, and also Ruby, Rena, their mother Siya, the third heroine, Yua and her mother, and the fourth and fifth heroines.