Pax Dei, the medieval fantasy social sandbox MMOMMO. Massively Multiplayer Online — a game that hosts very large numbers of players together in one shared, persistent world. from Mainframe Industries, officially launched on October 16, 2025, exiting a Steam Early Access period that began on June 18, 2024. The Windows-only title is co-published by Mainframe Industries and New Tales, and is built on Unreal EngineUnreal Engine. A widely-used commercial game engine from Epic Games; powers many large-studio (AAA) games. UE5 is the current generation. 5.
Gameplay & Economy
Pax Dei is set in a fantasy medieval era and centers on a fully player-driven economy. Every item in the game world is player-crafted, requiring players to gather their own materials for weapons, armor, and construction. There are no non-player characters dispensing quests; instead, the environment contains lore and mysteries for players to discover and solve independently or collaboratively.
Players take the role of humans and can work alone or with others toward common goals. Construction is permitted in designated zones called Heartland valleys, where players are allocated plots of land that can be developed individually or cooperatively.
Development Background
Mainframe Industries was founded in Helsinki, Finland, in 2019, with additional studios in Reykjavík, Iceland, and Paris, France. The studio first announced Pax Dei in March 2023, followed by a closed playtest and a closed alpha running from November 14 to November 26 of that year. The Early Access release in June 2024 drew mixed reviews, leading to a 16-month refinement period before the full 1.0 launch.
Platform & Availability
Pax Dei is available exclusively on Windows via Steam. The October 16, 2025 launch marks the transition from Early Access to full release, with Mainframe Industries framing the milestone as the start of a new chapter for the sandbox MMO.