Amnesia Labyrinth, Vol. 1 (Amnesia Labyrinth #1)
by Nagaru Tanigawa, Natsumi Kohane (Illustrator)
When high school student Souji Kushiki, an academic achiever and talented athlete from a well-to-do family, returns home from summer vacation, he finds that his sisters Harumi, Youko and Saki have changed. Their strangely clingy behavior borders on the inappropriate and bizarre, yet Souji just brushes off their mysterious conduct at first.
However, when Souji arrives at school the next day, he learns that, during the summer, three students were murdered by an unknown culprit. Are the victims linked, and could Souji’s sisters have anything to do with the murders?
With the help of his cheery and spunky new girlfriend Yukako Sasai, straight-laced Souji is about to venture into a mysterious world that might just be the death of him. Summary from Goodreads.
Zenbu Chodai, vol. 1 by Haruko Kurumatani
Sakura Himeko has been treated as a queen for her whole life. She is beautiful, smart, and good at sports. People classify her as perfect. She says that if someone wants to be her boyfriend, they must be as perfect as her. When she transfers to a new school, she meets Ozora Ren, who is as perfect as her, maybe even better. She not only wants to stay #1 but she also wants him to fall for her. Summary from Goodreads.