Kokushi no Shima

A non-fiction writer named Shiho Katsuragi visits Shikibu Takeru in Tokyo, hands him a key to her apartment, and requests he manage her belongings if she doesn't return in three days. She does not return, and no one knows her whereabouts. Takeru investigates and learns from two witnesses that Shiho was seen boarding a ferry to a place called "Island Kokushi" near Kumamoto with another woman. Concerned, he travels to the island to search for her. He encounters an environment filled with ancient customs, an unusual religious practice, and multiple unexplained deaths. The manga adapts a novel series by Ono Fuyumi, known for *Ghost Hunt*, and follows a similar suspenseful and eerie narrative style. The term "Kokushi" appears to be an original term from the author, loosely suggesting a belief in a deity not officially recognized.