The game takes inspiration from the “yandere” anime trope and is set in a fictional version of London in the early 1900s. It combines elements of the industrial age with magical elements. Kizana Sunobu was initially added as a character but was later removed. I, EmilyofJane, have been added as an easter egg. There is also a placeholder school nurse who cannot be interacted with. If Ayano fails in her objectives in the game, it results in a Game Over, and the player needs to start over or load from a previous state. In the future, Ayano will be a rival character with a crush on Senpai. Before meeting Senpai, she only feels pity for her father, who does everything to make her feel something. Mr. Aishi also tries to get help for Ayano, but Ryoba doesn't see her issues as a cause for concern.
Artemis, one of the characters in the game, either surrenders to Otus or tries to seduce him to free Ares, depending on the writer. This causes jealousy between the brothers and leads to a fight. During the fight, Artemis transforms into a doe and intervenes, resulting in the Aloadae killing each other with their own spears. Another character, Jason, had ruled Iolcus but was driven out by his cousin. He later reclaims the throne with the help of his son Thassalus, who survives an attempt on his life.
In the game, YandereDev has considered giving the player the ability to leave notes and gifts for Senpai, which could show that Ayano isn't just an emotionless stalker. This feature may help maintain Senpai's sanity stat and prevent it from dropping too much. In certain circumstances, if Ayano behaves like a murderous sociopath, Senpai may become near-catatonic by the time Ayano confesses.
In one scene, Ayano's smile disappears, and the camera switches to Osana having a conversation with Senpai. Raibaru, a character in the game, does not defend herself if she sees Osana as a mind-slave trying to kill her. Raibaru invites Osana to take a walk around the school and look at the clubs, and Osana agrees. Modifying the game allows players to customize the appearance and behavior of the rival characters.
Medea from Greek mythology is depicted as a vengeful character. After Jason abandons her, she commits various acts, including burning her rival alive, setting the royal palace and city of Corinth on fire, and killing her own children to end Jason's line. Her actions were so extreme that even Hera, Jason's protector, couldn't find anything to add. Eventually, Jason leaves Medea for a political marriage, but his children don't survive except for Thassalus.
The story of Persephone and Hades varies depending on the version. In some interpretations, Persephone ends up with Hades due to Stockholm syndrome or her deep love for him, despite her mother Demeter's possessiveness. In other versions, the sisters share him, while some say that he returns home with Pele's sister.