The Ashes of My Flesh and Blood is the Vast Flowing Galaxy

One day, Kiyosumi Hamada, who is preparing for his university entrance exam, witnesses a first-year girl being bullied at a school assembly. Kiyosumi intervenes. However, what awaited him was a scream of "Aaaahhhhh!" from Hari Kuramoto, the underclassman who should have been glad to be saved. What is the meaning of her rejection? Who are the "two dead people"? Eventually, Kiyosumi discovers the true nature of the incident, and Hari's true nature…

(Source: Shincho Bunko, translated)