Overgrown Ruins
The Overgrown Ruins is a biome on Planet Zezura in Subnautica 2. It features ancient structures that have been overtaken and reclaimed by Zezura's native marine life and flora. The biome's name was spotted in dev vlog file names by community members and quickly became one of the most discussed environments, primarily because the presence of ruins raises fundamental questions about Zezura's history: who built them, when, and why did they abandon them?
What the name tells us
The biome name contains two key descriptors. "Ruins" confirms the presence of artificial structures, meaning an intelligent civilization built something on Zezura at some point in the past. "Overgrown" means those structures have been reclaimed by the planet's biology over a long period of time. This is not a sterile archaeological site but a biologically active zone where flora and fauna have colonized the architecture, integrating it into the living ecosystem.
This combination of ancient construction and thriving biological growth makes the Overgrown Ruins a likely source of both advanced technology (for the Scanner blueprint progression) and unique creatures adapted to living among the structures (for the Biosampler DNA adaptation progression).
Possible Architect connection
The Architects (also called Precursors) are an advanced alien civilization central to the Subnautica franchise. They maintained research outposts across multiple worlds, connected by teleportation technology. On Planet 4546B, their abandoned facilities (the Quarantine Enforcement Platform, Disease Research Facility, Alien Thermal Plant, and Primary Containment Facility) drove the plot of the original game.
The Overgrown Ruins on Zezura may represent a similar Architect presence on the new planet. If the Architects built research facilities across the galaxy as part of their search for a Kharaa Bacterium cure, Zezura could have been one of their research sites. The ruins being "overgrown" suggests they were abandoned long ago, which is consistent with the Architects' history of retreating from worlds after the Kharaa devastated their civilization.
However, the ruins could also belong to an entirely different civilization, one previously unknown in the Subnautica universe. Zezura is a new planet with its own ecosystem, and the structures may predate or have no connection to the Architects. The game's narrative designer Seth Dickinson has not disclosed the ruins' origin.
Narrative significance
The Overgrown Ruins are among the most narratively significant biomes on Zezura. The Steam store page for Subnautica 2 asks: "What creatures, intelligent or otherwise, await your arrival? What happened here?" The ruins are a direct physical answer to the "what happened here" question, suggesting that Zezura has a history that predates the player's arrival by a significant margin.
If the ruins contain data terminals, lore entries, or scannable technology (as the Architect facilities did in the original game), the Overgrown Ruins biome will likely be a key location for story progression. The PDA encyclopedia entries from scanning alien technology provided much of the original game's world-building, and a similar approach in the ruins would connect Zezura's past to the present-day crisis of the Blight.
Environment design
The biome's concept, ancient architecture colonized by alien marine life, represents a distinctive design challenge. Dev Vlog 2 ("Building Unknown Worlds") showcased the environment team's custom tools for creating Zezura's terrain, including MeshBlend (seamless asset blending) and the Tufa Kit pipeline (detailed rock formations). For the Overgrown Ruins, these tools would need to handle the intersection of geometric, artificial structures with organic, biological growth, a more complex visual challenge than purely natural biomes.
Like all of Zezura's biomes, the Overgrown Ruins are entirely handcrafted. The deliberate placement of every structural element, biological growth pattern, and creature spawn point allows the developers to create specific moments of discovery as players explore the ruins.
Community speculation
The Overgrown Ruins generated more community speculation than any other biome name when the list was discovered. Players asked: "Ruins of what? The Precursors' stuff? Old human stuff? Something else?" The ambiguity of the name is intentional; it invites curiosity without revealing whether the structures are Architect, human, or from an unknown source.
The "overgrown" aspect also sparked interest in what kind of alien flora has colonized the structures, whether the biological growth affects gameplay (obscuring pathways, hosting unique creatures), and whether the ruins contain functional technology that the player can interact with or only archaeological remains.
What remains unknown
Who built the ruins (Architects, humans, or an unknown civilization)
When the ruins were built and when they were abandoned
Whether the ruins contain scannable technology, data terminals, or lore entries
Specific depth range and placement in Zezura's progression
Unique creatures and resources in the biome
Whether the ruins have any connection to the Blight's origin or spread
How large the structures are and what their original purpose was