Meitantei no Jouken

In the second year of high school, the homeroom teacher dies in a murder case. The main character, Maoka Riku, is elected to a troublesome committee and soon finds himself involved in a murder case. Who killed my homeroom teacher?

"The Apothecary Diaries" author Natsu Hyuuga's new frontier! --- A Cannibalism Comedy with Supernaturals × an Immortal Girl × Death Flags "Hey... What kind of meat is this?" Set in modern-day Japan — though it’s a world where supernatural beings like werewolves and vampires live quite normally. A sixth-grade girl named Yukiko, who is preparing for her junior high entrance exams, suddenly gets a new transfer student in her class. The boy, who introduces himself as Fushio Yamada, is actually the son of the Immortal King. One day, Yukiko is attacked by a man-eating monster while trying to save a classmate, but is rescued by Fushio.However, as the price for saving her life, Yukiko ends up no longer human, but an immortal being herself. This is the story of an immortal girl and the son of the Immortal King as they face all kinds of death flags together.

The story of "The Apothecary Diaries" from Xiaolan's perspective. (Source: Manga UP! Global)