Hitokui Magical: Satsuriku Kijutsu no Niounomiya Kyoudai

The world’s most feared assassins, the Niounomiya siblings, have finally arrived. Drawn by an unusual request, Ii—a man known as the Nonsense User—is invited to observe a deeply unsettling research project. His destination is the abandoned ruins of a clinic in northern Kyoto, and he is joined on this expedition by Ichihime Yukariki and Kasuga Kasugai, two residents of a peculiar antique apartment building. Their objective centers on Assistant Professor Kigamine, whose singular academic pursuit defies all logic: researching how to never die. At the heart of this bizarre study is Kuchiha Madoka, a girl burdened with eternal life. Yet what begins as a simple observation mission quickly spirals beyond their control. Instead of uncovering the secrets of immortality, the group finds themselves confronted by a terrifying destiny that threatens to consume them all. As the legendary killers make their dramatic debut, the line between survival and slaughter vanishes entirely. This thrilling coming-of-age story plunges its characters into a nightmare where fate itself becomes the ultimate adversary, testing everything they thought they knew about life and death.