Platinum End

One day, Naho Takamiya receives a letter written to herself from ten years in the future. As Naho reads on, the letter recites the exact events of the day, including the transfer of a new student into her class named Kakeru Naruse. The Naho from ten years later repeatedly states that she has many regrets, and she wants to fix these by making sure the Naho from the past can make the right decisions—especially regarding Kakeru. What's more shocking is that she discovers that ten years later, Kakeru will no longer be with them. Future Naho asks her to watch over him closely.

Ai, a young girl with shut-in tendencies, who tries not to interact with others. She keeps one of her eyes hidden behind her hair. One day, she happens to stop by a deserted arcade, where she meets "Aka." Spinning the gacha at their urging, she acquires a "Wonder Egg," and from that moment, her fate begins to change...

A supernatural system allows people to take revenge by having other people sent to Hell via the services of a mysterious entity and her assistants who implement this system. Revenge, injustice, hatred, and the nature of human emotions are common themes throughout the series.

To be united with her crush, a hopeless romantic summons the ghost in the girls' bathroom at her school. But she's shocked when the ghost is a boy!