Samayou 8

There are parasites that transform into their hosts' loved ones to feed off of them. Eito, who lives mimicking the host he killed for his inability to love him, meets fellow parasite Hachi. Although Hachi lives more like a stray cat, their circumstances are similar, and Eito starts to grow attached as they work together. Wishing to stay by his side, Eito enters a physical relationship with Hachi, but even then Hachi's feelings remain unclear to him.

While grappling with their complicated relationship, Eito starts to wonder if finding food might not be Hachi's only goal...

(Source: Tokyo Mangasha, translated)