Shinkai Protocol
A DnD cyberpunk submarine exploration game set on Nereus, a frozen ocean world where prisoner colonists build underwater societies beneath the ice. Japanese/cyberpunk aesthetic meets psychological horror and dark comedy - inspired by Barotrauma. Dive deeper. The abyss remembers.
Dive Deeper. The Abyss Remembers.
On Nereus, a frozen ocean world beneath endless ice, prisoner colonists carve out fragile societies in the deep. Take command of a battered submarine, build a crew from unlikely survivors, and descend into waters haunted by ancient forces, corporate power, and the things people become when rescue is no longer coming. Shinkai Protocol is a cyberpunk D&D adventure of exploration, psychological horror, dark comedy, and impossible choices.
EVENT: 甲号開拓演習 — Kōgō Kaitaku Enshū, “Alpha-Class Frontier Exercise” OPEN ALPHA EVENT • Ends October 4, 2026
PUBLIC NOTICE — BY ORDER OF THE SHINKAI PROTOCOL AUTHORITY
All registered colonists are hereby invited to participate in the Alpha-Class Frontier Exercise. Explore Nereus, test its systems, survive its hazards, and report your findings. Playing during the Open Alpha, discovering problems, and providing feedback can earn exclusive achievements, event gear, and experimental equipment. Some rewards may follow you to future characters. Others will remain with the unfortunate individual who earned them.
Your vessel is a test platform. Your crew is a data-gathering unit. Your survival is statistically valuable. The Authority does not require your enthusiasm. It requires your participation. Report what works. Report what breaks. And if you somehow manage to break something that was not supposed to be breakable, please inform the appropriate personnel before attempting it again.
— Office of Deepwater Operations, Haken Bakufu
**BEACON UPDATE SERIES — Phase active:** Currently testing submarine travel to and from the beacon station. Expect submarine and narration mechanics to change during this time; updates released weekly where possible.
Current Version: Open Alpha 2.9 (Beacon Series) — Added additional characters and one location to Shinkai Station to liven up the place. Completely revamped the relationship system from scorecards to detailed dossiers. Now everyone has a personal thought on those they know, which means now it'll take more work to get on peoples good sides, and people will not fully acknowledge you if your new.
This project is currently in Open Alpha to test core game mechanics. Please leave your feedback in the Discord. Content is actively being developed while we focus on making the game functional and fun for our players.
Discord: https://discord.com/channels/1490398767587918017/1540774022508445836
Recommended Ultra Sub / high credit roller model: Gemini 3.8 Flash (may sanitize mature scenes) Recommended standard model: GLM 3.5 flash (It takes time to think so will have slow wait times) Recommended "Not slow" Core models: Mimo v.25 or Muse Spark 1.3 Recommended image model: GPT Image 2
Kurogane Station
Drag to pan, scroll to zoom. Click a marker to open it — places with maps of their own take you deeper.