Development History

Overview

The development of The Expanse: Osiris Reborn by Owlcat Games began in 2021 and represents the studio's most ambitious project to date. Transitioning from isometric CRPGs (Pathfinder: Kingmaker, Pathfinder: Wrath of the Righteous, and Warhammer 40,000: Rogue Trader) to a third-person action RPG required nearly a year of prototyping, a complete engine switch from Unity to Unreal Engine 5, and a massive expansion of the development team. The project has involved partnerships with Alcon Interactive Group (the holders of The Expanse intellectual property), consultation with a former NASA astronaut, and collaboration with actors from The Expanse television series.

Development Timeline

The following table tracks the major milestones in the game's development from its inception through the closed beta launch:

Team and Technology

The shift from isometric CRPGs to a third-person action RPG was not simply a change in camera perspective. It required Owlcat Games to rethink nearly every aspect of their development pipeline. The studio spent close to a year building prototypes before settling on the final design direction. During this prototyping phase, six different combat system prototypes were tested, each exploring different approaches to third-person shooting, ability usage, and squad mechanics before the team converged on the final system.

The engine transition from Unity (used for all of the studio's Pathfinder titles) to Unreal Engine 5 was one of the largest technical undertakings in the project. CTO Alexey Drobyshevsky led the UE5 modifications, with a particular focus on zero-gravity systems. Standard game engines are built with the assumption of a flat plane and consistent downward gravity. To support the full range of zero-gravity movement and physics that The Expanse setting demands, Drobyshevsky and his team rewrote major engine components to eliminate that assumption entirely.

To support the scope of the project, the Owlcat Games team grew from approximately 100 employees to over 450, with more than 280 people working directly on Osiris Reborn. This makes the project three to four times larger than any previous Owlcat title in terms of team size. The studio also brought on key hires from CD Projekt Red, adding experienced developers who had worked on large-scale open-world RPGs.

Collaborations

The game is developed in partnership with Alcon Interactive Group, which holds the rights to The Expanse intellectual property. This partnership provides Owlcat Games with access to the source material, lore bible, and creative oversight needed to ensure the game is faithful to the books and television series.

To ensure authenticity in the game's depiction of space travel and zero-gravity environments, Owlcat brought on former NASA astronaut and International Space Station commander Leroy Chiao as a consultant. Chiao, who spent over 229 days in space across four missions, provided detailed feedback on multiple aspects of the experience. His contributions covered the physical sensation and fear of extravehicular activity (EVA), the behavior of mag boots on station surfaces, how movement feels and looks in microgravity, and the nuances of sound design in space (where sound does not travel through vacuum but does transmit through solid contact with surfaces). A developer diary featuring Chiao's involvement was released in November 2025.

Music and Sound

The game's score is composed by Pawel Perepelica, who previously composed the music for Owlcat's Pathfinder: Wrath of the Righteous and Warhammer 40,000: Rogue Trader. His familiarity with Owlcat's storytelling style and pacing made him a natural fit for the project. The main theme for The Expanse: Osiris Reborn was revealed publicly on November 7, 2025.

Sergey Eybog is the Audio Director, overseeing the broader soundscape of the game. The audio team worked closely with Leroy Chiao to ensure that the depiction of sound in space environments is grounded in physical reality. In vacuum, there is no sound propagation through air, but vibrations do travel through solid surfaces. This principle influenced how the game handles audio during EVA sequences and in depressurized areas.

Awards and Recognition

Even before entering beta, The Expanse: Osiris Reborn received significant industry recognition. In October 2025, the game was nominated for two categories at the Golden Joystick Awards 2025:

These nominations came on the strength of the presentation trailer that debuted at the Future Games Show in June 2025 and the positive reception from the Gamescom 2025 hands-on previews. Being nominated in the Most Wanted Game category alongside other major upcoming titles reflected the high level of anticipation surrounding the project.

TV Series Connection

Some actors from the 2015 Expanse television series will reprise their roles in Osiris Reborn through voice acting and digital scanning. Game design director Leonid Rastorguev confirmed this, stating: "Some of them will be voiced by their original actors from the show, and they'll be giving their appearance to those characters with digital scanning." This means that certain characters in the game will look and sound like their TV counterparts, providing a direct visual and auditory link between the show and the game.

As of the closed beta launch, no specific actors have been officially named by Owlcat Games. The studio has kept details about which performers are involved under wraps, likely to allow for a larger reveal closer to the full release. The involvement of the original cast is expected to appeal strongly to fans of the television adaptation who want to see familiar faces in the game's narrative.

Generative AI Controversy

Following the March 26, 2026 Xbox Partner Preview show, Owlcat Games confirmed that they use generative AI tools during the development process. According to the studio, AI is used for prototyping, testing ideas, and creating temporary placeholders during the development pipeline. PR manager Katharina Popp addressed the topic directly, stating: "Everything in the final version will definitely 100 percent be human-made."

The studio specified that generative AI is not used for writing or voice acting. The tools are employed in the earlier stages of development where rapid iteration is needed, such as generating rough concept variations or placeholder assets that are later replaced by human-created content.

Despite these assurances, the confirmation sparked significant community backlash. Many gamers have taken a firm stance against the inclusion of AI in any stage of game development, viewing it as a threat to human artists and a potential quality concern even when the final output is hand-crafted. The controversy mirrors broader industry debates about AI usage in creative fields and reflects the sensitivity of the topic within the gaming community.

Key Personnel

The following individuals have played central roles in the development of The Expanse: Osiris Reborn:

Engine Choice and Studio Firsts

The move to The Expanse: Osiris Reborn put Owlcat Games on an engine and a genre the studio had not previously shipped. Their earlier isometric CRPGs, Pathfinder: Kingmaker, Pathfinder: Wrath of the Righteous, and Warhammer 40,000: Rogue Trader, were built on different toolchains tuned for fixed-camera, rules-heavy party games. Unreal Engine 5 brings strong support for cinematic lighting, destructible environments, and the station-scale traversal that the setting demands, but it also imports the now-familiar Unreal Engine 5 pain points: traversal micro-stutter and localized frame dips when dense physics and destruction setpieces unload at once. Both are visible in the closed beta build, and the studio is actively profiling them during the beta window rather than treating them as shipped behavior.

A third-person cover-based action RPG is also a first for the studio. To support the transition, the team brought in developers with prior action-game experience from other studios instead of retraining its existing CRPG staff on shooter-style systems from scratch. That hiring pattern is reflected in how the combat and gameplay systems are layered on top of the familiar Owlcat stat and choice architecture: the moment-to-moment feel draws on conventional cover-shooter vocabulary, while the build, persuasion, and branching-outcome design stays recognizably Owlcat.

Team Scale-Up for Osiris Reborn

The development team has grown to roughly 450 people for this project, several times the size of the crews that shipped the studio's earlier Pathfinder titles and Warhammer 40,000: Rogue Trader. The ramp is not purely additive headcount. It includes new discipline coverage for animation, cinematics, third-person shooter feel, and destructible-environment tech, alongside the writing, quest design, and systems depth that Owlcat has delivered on previous projects. Studio-wide context and leadership detail lives on Owlcat Games.

Project Milestones Reflected in the Closed Beta

The beta window in April 2026 is the point where a wide press and founder audience first touches the game hands-on. The table below captures the main public milestones reflected in the build, dated approximately from the material available during the beta period. Founder tier detail lives on pre-order editions, and the beta mission scope lives on closed beta.

Feature Pillars Committed for Launch

The closed-beta build is a narrow slice of a much larger promised experience. Several feature pillars have been publicly described by the developer and are grounded, in part, in systems that already appear in the beta. These are the pillars to expect at full release.

• Three playable origins. Earther, Belter, and Martian backgrounds will be selectable in the full character-creation flow. The beta only exposes Earther and Belter presets. Gender selection in the final game mirrors the twin sibling, so the player and J always match gender.

• Seven recruitable companions. Full roster coverage with romance options and personal quests. See companions for the confirmed member list.

• Four combat and six social or exploration skills. Shooter, Gadget, Survivalist, and Leader trees handle combat progression. Persuasion, Athletics, Cyber Sabotage, Perception, Analysis, and Engineering handle the non-combat layer. Deeper structure lives on character creation and progression.

• Environmental-exploit combat. Four companion-exploit categories, Precision, Demolitions, Malfunction, and Cyber Attack, plus ship-based fire support from the Gemini's PDCs. Full mechanics live on the exploit system.

• Three-grade weapon workbench and blueprint fabrication. Players spend scavenged materials to upgrade every weapon in three grades, with each grade offering a small perk choice, and spend found blueprints to fabricate new subsystems at the workbench. Full detail lives on weapons and equipment.

• Full voice acting. Full English voice acting with localization into Spanish, French, Russian, simplified Chinese, and German for launch. Audio-layer detail lives on sound design and zero-gravity mechanics.

• Multiple visitable locations. Visits across Eros (story backdrop), the new Pinkwater Four Station, Ceres, Ganymede, Mars, Luna, and asteroid-belt bunker complexes. Full travel map lives on locations.

Platforms and Distribution

The target platforms at launch are PlayStation 5, Xbox Series X|S, and PC via Steam, GOG, and Epic Games Store. Xbox Game Pass day-one availability has been confirmed, so the title will be playable on the service at release without a separate purchase on Xbox Series X|S and on PC through the Xbox app. The closed beta runs on Steam, PlayStation 5, and Xbox Series X|S for founder-tier holders.

Beta Feedback Priorities Stated by the Developer

The beta is framed as a feedback-collection window rather than a server-load test or a performance show. Several priorities have been publicly named by the studio during the developer-reacted beta overview.

The studio has been clear that the state of the beta does not reflect the state of the final game and that iteration on UI, control scheme, animation polish, and voice-over coverage is planned between the beta window and release.

Design Leadership Visible in the Beta Presentation

The developer-reacted beta overview was presented by Game Design Director Leonid Rastorguev, who walked through the Pinkwater Four Station mission and summarized the combat, progression, and exploration layers for the founder audience. Lead Game Designer Grigory Ponomarev co-presented, focusing on combat pacing, weapon-loadout philosophy, gadget tactics, and squad-command ergonomics. Together, the pair invited founders to experiment with different builds, playstyles, and dialogue options across the Pinkwater Four Station mission and to send back feedback that the studio could fold into iteration before launch. The presentation was used both to frame what the beta includes and to invite structured feedback on the areas listed above.