Also known as Shuumatsu no Harem. Manga by LINK and Kotaro Shono.
Diagnosed with multiple sclerosis, young researcher Reito Mizuhara is to be put into cryosleep until a cure can be found. Short on time, Reito decides to confess his pent-up feelings to his childhood crush Erisa Tachibana and bids farewell to his family and friends. As Reito goes to sleep and his consciousness begins to fade, Erisa barges into the room and declares that she will wait for him.