Core Keeper Biomes Guide: All 9 Regions, What To Bring and What To Expect

Every world is generated around the Core, and the layout repeats with a logic you can navigate by. The Core sits in The Undergrounds, the starting biome. Around it runs a full circle of chasm: one unbroken gap you cross on wooden bridges. Beyond that chasm, the first ring is split in two: one half is the Clay Caves, the other half is the Forgotten Ruins, and the two sit opposite each other. That single fact saves hours of confused digging. If your first crossing lands you in grey ruins stone that your copper pickaxe barely scratches, the tin you actually need is on the far side of the world: circle around the ring instead of grinding forward.

Beyond the opening ring stands the Great Wall, the hard border between the inner and outer worlds. It stays shut until the Core is powered, and that is by design: iron is the gear ceiling of the inner game, and no higher-tier material can be dug before the wall opens. Once it does, the rings resume at a larger scale: three big outer biomes themed around a Titan each, then a crystal band, then the outermost shell, then one final region added after launch. Section 2 takes them in order.

Where every explorer wakes up, wrapped around the Core itself. The walls are dirt and soft stone you can dig from the very first minutes, the roots tangled around the Core give your first wood, and the ground holds the game's first ore, Copper. The wildlife sets the tone: orange and red slimes and Shrooman wander here, most of them neutral until provoked, with red slimes the early exception that attacks on sight. There is no entry requirement at all. This is the biome that teaches you digging, lighting and hunger before anything out there tries to kill you for real.

The first half of the ring beyond the chasm, and the home of Tin, with gold appearing at this level too. Come with copper-tier gear and a wooden bridge for the chasm crossing. The caves are swarming with Larva, which are weak individually and dangerous in the packs they travel in, and your first Cavelings appear here as well. Tin is the tier that cracks the ruins across the ring, so a Clay Caves trip is really the key to the second half of the early game. Deep inside this biome sits the Larva Hive sub-biome, covered in Section 3.

The second half of the inner ring, sitting opposite the Clay Caves, and the source of Iron, with gold fully usable from this tier. Entry asks for a tin-tier pickaxe: the grey ruins stone is harder than Clay Caves walls and shrugs off copper. Inside, Cavelings stop being a novelty and become the population: warriors, shamans and brutes patrol the broken halls in groups. Iron is the ceiling of everything before the Core wakes, so clearing the Ruins properly, workbench and full gear set included, is the natural finish line of the opening act.

The first of the great outer biomes, and the first one the Great Wall was keeping from you. Entry requires a powered Core and a way through the Great Wall; arriving before that moment is not a shortcut, it is a wall. The prize is Scarlet ore, which needs the Smelter Kiln to refine. The Wilderness is a living biome: Caveling Hunters that disguise themselves, Gardeners, purple slimes and Snare Plants all share the greenery, and it stays dangerous in a way the inner rings never were. This is also where the game's Titan arc begins in earnest, with Azeos itself waiting at its arena.

A biome where the ground mostly stops. The Sunken Sea is open water dotted with islands, its signature ore is Octarine, and its signature problem is movement: the shallows carry a slippery debuff that slows you on foot, so a boat is required equipment, and the Boat Workbench that builds it is a Scarlet-tier product. In other words, the Wilderness pays for the Sea. Tentacles, Bubble Crabs and blue slimes own the water, and the Sea Titan Omoroth waits out in it. Pack for sailing trips, not digging trips: your time here is spent crossing between islands rather than tunnelling under them.

Sand, ruins and the Galaxite tier. The Desert sits beyond the Great Wall like its ring-mates, and its ore hides inside sandstone walls, so you need digging power of the current tier to extract it at all. Bomb Scarabs skitter between the dunes, and Caveling Assassins and Mummies hold the buried structures. The Desert is also unusually dense with named places: the Oasis sub-biome and the Molten Quarry both sit inside it, which makes it the outer biome you will revisit most often on side trips.

The crystal band. The Frontier wraps around the outer biomes as a ring, with smaller pockets of it also embedded deep inside those biomes, so you will meet its glowing ground more than once. It is the source of Solarite, the tier between Galaxite and Pandorium, and of Gleam Wood. Mimites, Orbital Turrets, Nilipedes and Crystal Snails patrol the crystal fields, and the crystal walls themselves demand late-game digging gear. Exactly which pickaxe tier the game asks for here is something the official wiki leaves unstated, so treat the Frontier as a place your Galaxite-era kit graduates into, and let the walls tell you when you are ready.

The outermost shell of the original world, and the home of Pandorium, the final ore of the main material ladder. The Passage is dark, strange and defended by Sulfur Worms and Colossal Amoebas. Its defining gate is the ground itself: the Fossil Blocks here require late-game digging equipment to break, per the official wiki, so arriving early means staring at walls your pickaxe cannot touch. Pandorium gear made here is the kit the end of the main story is balanced around, and the biome reads like it knows it: this is the last ring of the world as it shipped at 1.0.

The ninth biome, added in update 1.2, and the furthest ground in the game: a mechanical region at the far north of the map, beyond the Passage. Its ore is Relucite, an expansion tier that sits outside the original eight-tier ladder, its hostiles are three types of Geobot plus Void-themed enemies, and its walls need late-game digging equipment. Breaker's Reach is post-game territory in practice: its two bosses, S.A.H.A.B.A.R. and Oblidra the Void Lord, are both post-game fights, and the official roadmap already points one step further, with update 1.5 set to open a new biome beyond the Reach. Come here when the main story is done and your Pandorium kit feels finished.

Inside the nine main biomes sit smaller named zones. Eight sub-biomes are confirmed across the sources this guide is built on; each one below is a place with its own reason to visit.

Two of these earn a second mention. The Larva Hive is the one sub-biome most players go looking for by name, because the Hive Mother sits at its heart and a scanner exists specifically to find her once you can build the right station. And the Oasis punches above its size: a post-game boss dungeon and a unique cattle species in one small patch of green, inside the biome most players otherwise cross at speed.

Nine main biomes in the current version: the original eight from the 1.0 world, plus Breaker's Reach, added in update 1.2. On top of those, eight sub-biomes are confirmed: Meadow, Larva Hive, Mold, Forlorn Metropolis, Molten Quarry, Oasis, Moss and Void.

Follow the rings and the tier names the biome: Copper in The Undergrounds, Tin in the Clay Caves, Iron in the Forgotten Ruins, Scarlet in Azeos' Wilderness, Octarine in the Sunken Sea, Galaxite inside the sandstone walls of the Desert of Beginnings, Solarite in the Shimmering Frontier, and Pandorium in the Passage. Relucite sits outside that ladder in Breaker's Reach.

No, and the walls are the reason. Each biome's rock needs the pickaxe tier funded by the previous biome's ore, and the Great Wall hard-locks the outer world until the Core is powered. The order in Section 2 is the order the game enforces.

No. Breaker's Reach is post-game ground: it sits beyond the Passage at the far north of the map, and its bosses S.A.H.A.B.A.R. and Oblidra are post-game fights that come after the Core Commander. Visit it when the main story is finished, not on the way through.