The premise
Saint Hadria is the last sealed city on a drowned coast, eight years into the age of the Titans - colossal living things the size of skyscrapers that rose from the ocean trenches, drowned the world's coasts, and shattered its armies. The survivors of a whole region now shelter behind the Bulwark, a vast improvised seawall ringing the one harbor city that held: four million people, rationed power, dwindling food, and the monsters circling closer each season. You are one of the survivors who keep the city breathing - a Bulwark wall-warden, a scavenger working the drowned districts beyond the line, or a refugee with nothing but the will to live.
The Bulwark Authority under the hard, unbending Marshal Kaelen Jax runs the seawall and martial law, and will sacrifice any district to keep the city alive. The Hadria Combine, under Director Valerius Marchetti, controls power and water and sells survival by the liter. The Deepwatch Institute, where xenobiologist Dr. Aris Vance tracks the signals the Titans send through the deep, knows something about why they are circling. The Drowned Run crews under salvage-boss Roric 'Scav' Bryn work the flooded ruins where the Titans walk. And the Leviathan Choir, led by the prophetess Morwen Kai, preaches that the monsters are gods and works to open the wall.
The largest Titan yet, the one they call the Sovereign, has changed course toward Saint Hadria, and the Bulwark will not hold against it. The city has perhaps a season. Every ration traded, every district given up, every promise made in the dark is logged.
What this world plays like
Your first ten turns are about staying alive long enough to matter. You find a corner of the Tenements or the Drowned Districts, you meet the Bulwark's people at the wall, you learn what a full canister of water trades for. Nobody trusts you yet. The city is already keeping score.
By turn fifty your standing with the Bulwark Authority, the Hadria Combine, the Deepwatch Institute, the Drowned Run, and the Leviathan Choir is tracked as real attitude, and the water you were given came out of someone else's ration. The crew you crossed on turn nine remembers. Deepwatch's desperate plan to turn the Sovereign aside has a price that is becoming clear.
By turn one hundred the Sovereign is near and the city is tilting. The Choir's congregation has doubled, the Combine is quietly preparing its own escape, and the rumor of a way to turn the Titan has become a plan with a terrible cost. Whoever you stood with, whoever you abandoned, Saint Hadria keeps the account.
Behemoth Bay does not reset between sessions. Close the tab. The horn-call still sounds out past the wall.
Factions in motion
The Bulwark Authority
The martial government of Saint Hadria, responsible for maintaining the city's defenses and enforcing order. The Authority sees survival as a war of attrition against the Titans and brooks no dissent, viewing any action that undermines morale or security as high treason.
The Hadria Combine
A corporate entity that seized control of the city's geothermal Power Spire and water purification plants during the First Rise. The Combine treats the survival of Saint Hadria as a business venture, controlling the economy through Scrip and ruthlessly protecting its assets and secrets.
The Leviathan Choir
An apocalyptic cult that worships the Titans as divine instruments of judgment, here to cleanse the world of humanity's sins. Drawing its congregation from the desperate and dispossessed Coastlanders, the Choir preaches surrender and actively sabotages the Authority's efforts to resist the 'Great Reclaiming'.
The Deepwatch Institute
The last remnant of pre-Rise scientific inquiry, composed of technicians and scientists who study the Titans. Operating on a shoestring budget, they monitor Titan signals and biology, convinced that understanding the enemy is the only path to survival, yet their dire warnings are often ignored by the city's leadership.
Drowned Run Crews
A loose confederation of salvagers, smugglers, and divers who operate in the flooded ruins beyond the city's secure zones. They are the masters of the black market, essential for acquiring rare parts and goods but officially designated as criminals by the Bulwark Authority.
People you'll meet
Director Valerius Marchetti
Marshal Kaelen Jax
Dr. Aris Vance
Morwen Kai
Roric 'Scav' Bryn
Joric Vane
Places that matter
Vance Heights
The administrative and residential heart of the Bulwark Authority, built on the city's highest ground. Clean, well-lit, and heavily fortified, with wide avenues patrolled by elite Wardens. The air here is cleaner, recycled by industrial scrubbers, a luxury unknown in the lower tiers.
The Spire Ward
Dominated by the humming, glowing Power Spire, this is the commercial and industrial engine of Saint Hadria. It's a district of stark contrasts: pristine Combine corporate offices loom over black market alleys choked with steam and desperate traders.
Locke's Reach
A quiet, isolated district dedicated to the Deepwatch Institute. It is a mix of repurposed university campuses and server farms, connected by covered walkways. The constant, low thrum of hydrophones and data processing equipment is the district's heartbeat.
The Tenements
A vast, densely packed residential sprawl of crumbling apartment blocks and repurposed harbor warehouses. The streets are narrow, perpetually damp, and tangled with illegal power lines. This is where most of Saint Hadria lives, breathes, and fears.
The Bulwark Line
The massive seawall itself and the ecosystem that has grown in its shadow. It is a frontier of constant repair, deafening sonic emitters, and watchtowers staring into the mist. In its lee are the Refugee Tiers, vertical shantytowns of stacked containers and scrap-metal shelters.
The Drowned Districts
The world beyond the wall. A graveyard of skyscrapers tilted like tombstones in the murky water, their upper floors forming chains of small, treacherous islands. A place of profound silence, broken only by the groaning of stressed metal and the distant, thunderous footsteps of the Titans.
A real turn from this world
Marshal Kaelen Jax does not look up from the wall-schematics. "You want a ration card and a bunk inside the line, you earn them," she says. "There's a breach team going into the Drowned Districts tonight for salvage Deepwatch swears we need. Half of them won't come back. You go, and we call your debt to this city paid."
She finally meets your eyes, and there is no cruelty in them, only arithmetic. The Sovereign is a season out and she has four million people and one wall.
Standing with the Bulwark Authority: pending. The debt is logged either way. In Saint Hadria, the city remembers who held the line and who ran.
Why Behemoth Bay holds up over a long campaign
Most AI roleplay tools are built around a single session. They start to fall apart at hour ten and are barely playable at hour fifty. Behemoth Bay doesn't, because the world isn't living in a chat history - it's living in a database.
Mechanical truth in Postgres. Coins, inventory, NPCs, factions, locations, properties - all in real database rows. The narrator describes around the database; the database is what's true. By turn 500, your business ledger still balances and your apprentices still have the names you gave them.
Hierarchical chapter compression. Every chapter compresses into a tight summary; summaries compress into act-level summaries. The hundredth turn can pull a relevant detail from chapter two without flooding the context window.
Semantic memory. Important moments are embedded as vectors. When the current scene references an old promise, the engine retrieves the exact exchange where that promise was made - even 800 turns ago.
You'll be asked to choose Quick Start or build a character of your own.