Gochousama! Ninomiya-kun

Ninomiya Shunko lives alone, having parents who love to travel around the world and an older sister with a wandering habit. One day, he is approached by a strange pair of siblings who simply state, "We'll be looking after you from now on," forcing him into cohabitation. These two harbor a significant secret: it is said that both the older brother, Tsukimura Mikihiro, and the younger sister, Tsukimura Mayu, possess a special constitution that requires them to absorb others' life energy to survive. However, because Shunko's older sister, Ninomiya Ryoko, and Mikihiro are old acquaintances, they completely ignore Shunko's objections and begin their shared life. Furthermore, since Mayu suffers from severe androphobia, Shunko is tasked with being her "bodyguard" to help her overcome this fear, again overruled by Ryoko and Mikihiro. Additionally, a love triangle begins to develop involving Shunko, Mayu, and Hojo Reika, the student council president at the school where Shunko and Mayu attend...