Dediri is a fishing village within the Blood Sea. It is situated east of Cinohshima on the northern edge of the Cometfall Sea. Off most maps and forgotten by trade routes, most people do not even know it exists and the residents stay isolated for a long time.

In 3E456, it was taken over by the Blackwood Institute and turned into a company town researching the ancient ruins found on the island. The Institute opened a portal to the Abyss in the island's central lake, which was eventually closed during the events of Sea of Starfall.