Xbox details how Starry Studio built Once Human’s biggest free expansion

Isles of Abyss is now available on Xbox Series X and Series S after its Oct. 22, 2026 release. The expansion is the largest free addition in the history of Once Human. The expansion moves the survival experience away from land and into a predatory ocean setting.

On Oct. 29, 2026, Xbox Wire ran a studio explanation of the expansion’s creation, describing how Starry Studio reimagined Once Human’s world design for the open ocean under its New Weird survival approach. Starry Studio’s design process started from one unsettling picture: a lighthouse placed where a lighthouse should not exist. Drawing on H.P. Lovecraft’s The Shadow Over Innsmouth, the team turned a familiar symbol of human safety into something watchful. Starry Studio wanted the sea to hunt players actively instead of acting as a blank corridor between islands.

Every part of the setting supports one guiding mood the team calls sinking into oblivion. That lighthouse image turned into an eye, and the eye demanded a body, so the body became the sea itself: a colossal living organism called The Sunken Lord.

Players move through five marine sectors, though one source counts four, and the environment systematically removes survival pillars such as vision, sanity, direction, gear, and solid footing. They stretch the game’s Stardust-polluted world into an uncanny ocean, and the sea itself behaves like a massive hostile entity that watches every move players make.

Ships become mobile sanctuaries, workshops, diving platforms, and artillery batteries through a modular building system that grants players full architectural control on the water. Players can build anything from quick skiffs that dodge whirlpools and escape anomalies to large floating fortresses carrying naval cannons, workbenches, and deep-sea diving equipment. Survival in the endgame spans three connected layers: sailing dangerous open water, finding uncharted islands, and diving into the abyssal seabed for rare parts and resources.

Drifting vessels like Sworn Never to Port and No Return Voyage serve as displaced organs that lost the ability to reach land, and strange lighthouses work as glaring eyes that follow players’ every move. Five unique ghost ships drift through the mist as tragic relics, and crews can board them to take blueprints.

Waking The Sunken Lord opens a four-player co-op raid inside the creature’s chambers, and it asks groups to dive below the surface to prove their combat skill. The finale asks squads to take on The Sunken Lord by breaking through its outer edge, fighting past moving tentacles and strange inner rooms, and diving straight into its heart.

A 21-day, two-phase community rhythm lets players purge anomalies to fill a shared server bar, and crossing the threshold wakes The Sunken Lord. Gathering hazards such as the vision-stealing Mist of Deceit and gear-corroding Time Rain gives players materials for survival technology, and defeating massive biomechanical lighthouses called Towers of Calamity opens higher crafting tiers.

A separate ocean-focused tech tree allows construction of self-sustaining mobile fortresses with electric propellers, harpoon turrets, smelters, and workbenches, and Fleet Co-Op supports cross-platform squad coordination. Players can capture Duet, a Deviant that manipulates the environment by shifting wind directions for better sailing.

Malla, an enigmatic navigator who says she has drowned a thousand times, shares six critical rules from her logbook that reveal the ocean’s deadly traps, including predatory lighthouses and disguised living islands. GameRant compared the expansion to Subnautica and Sea of Thieves, blending underwater exploration with naval combat and island treasure hunting, while the Sunken Lord raid resembles Sea of Thieves’ Sunken Kingdom.

The expansion costs nothing and launched at the same time on Android, iOS, PC (Steam), mobile, PlayStation 5, and Xbox Series X|S, with full cross-play and cross-progression enabled. Members of Xbox Game Pass Ultimate can claim an exclusive Once Human launch bundle from the Game Pass Perks gallery before November 18, 2026.

Once Human first appeared on Steam as a Windows release on July 9, 2024. Starry Studio and NetEase Games published it, and the Steam page shows three DLC entries.

Starry Studio said Once Human will be the first game in Green Game Jam 2027, which includes the Mr. Wish Driftpost community story event. The ESRB rates Once Human as Teen for Blood, Language, Suggestive Themes, Violence, In-Game Purchases (Includes Random Items), and Users Interact.