Dimensions

Naraka, the world you start in, is a loop of biome layers stacked along Y. Nine more dimensions sit outside it, each a single biome.

Naraka

One pass runs from Y −2,835 to 4,845. Above and below it the same layers repeat.

Void

Empty space. Climb past it and the loop starts again at Naraka.

Y range	Capture	Biome	Share of the layer	Day spawns	Night spawns
4,845 4,077 layers 24 to 22 layers 22 to 24		Null One biome file per layer: null_biome_2 null_biome_1 null_biome_0 Music: Silence	The whole layer	None	None

Cosmic

Y range	Biome	Share of the layer	Day spawns	Night spawns
4,077 3,821 layer 21	Cold Digital Space	25%	×0.2spawn rate	×0.8spawn rate
	Digital Space	25%	×0.2spawn rate	×0.8spawn rate
	Moon	25%		×0.1spawn rate
	Weird Digital Space	25%	×0.2spawn rate	×0.8spawn rate
3,821 3,565 layer 20	Digital Space	33%	×0.2spawn rate	×0.8spawn rate
	Mars	33%	×0.1spawn rate	×0.1spawn rate
	Moon	33%		×0.1spawn rate
3,565 3,309 layer 19	Digital Space	33%	×0.2spawn rate	×0.8spawn rate
	Mars	33%	×0.1spawn rate	×0.1spawn rate
	Moon	33%		None
3,309 3,053 layer 18	Alien	29%
	Dungeon Space	29%	×0.2spawn rate	×0.1spawn rate
	Moon	29%		None
	Island	14%
3,053 2,797 layer 17	Island	67%
	Alien	17%
	Moon	17%		None

Order

Y range	Biome	Share of the layer	Day spawns	Night spawns
2,797 2,541 layer 16	Dungeon 6	The whole layer	×0.05spawn rate	×0.05spawn rate
2,541 2,285 layer 15	Dungeon 6	The whole layer	×0.05spawn rate	×0.05spawn rate
2,285 2,029 layer 14	Dungeon 6	The whole layer	×0.05spawn rate	×0.05spawn rate
2,029 1,773 layer 13	Dungeon 6	The whole layer	×0.05spawn rate	×0.05spawn rate

Spirit Membrane

Y range	Capture	Biome	Share of the layer	Day spawns	Night spawns
1,773 1,517 layer 12		Spirit Structures: Church, Temple	The whole layer	None	None

Upper Heaven

Y range	Biome	Share of the layer	Day spawns
1,517 1,261 layer 11	Warp sky_warped_biome_3	44%
	Warp sky_warped_biome_4	44%
	Gallery	11%	×0.1spawn rate

Mid Heaven

Y range	Capture	Biome	Share of the layer	Day spawns	Night spawns
1,261 1,005 layer 10		Warp sky_warped_biome_2 Rain	57%
1,261 1,005 layer 10		Warp sky_warped_biome	43%

Lower Heaven

Y range	Biome	Share of the layer	Day spawns	Night spawns
1,005 749 layer 9	Tube Structures: Church	50%		None
	Ball	38%	×0.2spawn rate	×0.5spawn rate
	Sky Water Cube	13%

Plastic Membrane

Y range	Capture	Biome	Share of the layer	Day spawns	Night spawns
749 493 layer 8		Swan Structures: Church, Temple	The whole layer	None	None

Aether

Y range	Biome	Share of the layer	Day spawns	Night spawns
493 237 layer 7	Aether Structures: Church, Temple Snow	61%
	Rosary Snow	36%
	Caether Structures: Church, Temple Snow	3.0%	×0.9spawn rate	×0.8spawn rate

Surface

New worlds start here.

Y range	Biome	Share of the layer	Day spawns	Night spawns
237 −19 layer 6	Plain Structures: Sappy Town, Stone Fractal +12	9.5%	×6spawn rate	×2spawn rate
	Forest Structures: Stone Fractal, Hand Of God +2	3.7%		×1.5spawn rate
	Fruity	3.7%	×0.4spawn rate	None
	Rosary	3.7%	None	None
	Cplain cliff_plain_biome Structures: Sappy Town, Sponge +4	3.2%		×2spawn rate
	Lotus Happy Rain	3.2%	×0.2spawn rate	×2spawn rate
	Mangrove Structures: Stone Fractal, Hand Of God +1	3.2%		×1.5spawn rate
	Snow Structures: Fridge, Sappy Town Snow	3.2%	×0.2spawn rate
	Algae Structures: Pool Tower, Virus +1	2.6%	×2spawn rate
	Highway Structures: Sky Thing, Crystal Thing +1	2.6%	×0.3spawn rate	×0.5spawn rate
	Lain Structures: Sappy Town, Temple Snow	2.6%		×2spawn rate
	Ambiguous Biome Structures: Sappy Town, Skull +3	2.1%		×2spawn rate

Underground

Y range	Biome	Share of the layer	Day spawns	Night spawns
−19 −275 layer 5	Rosary	21%	None	None
	Lower Lotus	12%	×0.1spawn rate	×2spawn rate
	Meat Flower	10%	None
	Pool	10%	×2spawn rate	×2spawn rate
	Plain Structures: Sappy Town, Stone Fractal +10	6.9%	×1.2spawn rate	×2.2spawn rate
	Clown	5.2%	×0.5spawn rate	×0.1spawn rate
	Julia Snow	5.2%
	City	3.5%	×0.5spawn rate	None
	Dungeon 0	3.5%	×2spawn rate	×2spawn rate
	Dungeon 1	3.5%	×2spawn rate	×2spawn rate
	Dungeon 2 Music: Apsaras	3.5%	×2spawn rate	×2spawn rate
	Fudge Structures: Sappy Town	3.5%	×0.5spawn rate	×0.8spawn rate
	Slender	3.5%	None	None
	Sponge	3.5%	×0.8spawn rate	×0.6spawn rate
	Underground Farm Structures: Sappy Town Music: Farm	2.8%	None	×0.8spawn rate
	Melon Pillars Rain	1.7%	None	None

Lower Underground

Y range	Capture	Biome	Share of the layer	Day spawns	Night spawns
−275 −531 layer 4		Rosary	The whole layer	×0.8spawn rate	×0.8spawn rate

Silver Membrane

Y range	Capture	Biome	Share of the layer	Day spawns	Night spawns
−531 −1,043 layers 3 to 2 layers 2 to 3		Memory One biome file per layer: memory_biome memory_biome_2 Snow Music: Static	The whole layer	None	None

Naraka

The floor of the loop. Dig past it and you come out at the top of the Void.

Y range	Biome	Share of the layer	Day spawns	Night spawns
−1,043 −1,299 layer 1	Abyss	The whole layer
−1,299 −1,555 layer 0	Babel Music: Brown Noise	The whole layer	None	None
−1,555 −1,811 layer −1	Babel Music: Brown Noise	The whole layer	None	×0.001spawn rate
−1,811 −2,067 layer −2	Naraka Snow Music: Hell	The whole layer	None	None
−2,067 −2,323 layer −3	Wnaraka Structures: Shack Music: Hell	The whole layer	×0.5spawn rate	×0.5spawn rate
−2,323 −2,835 layers −4 to −5 layers −5 to −4	Naraka One biome file per layer: naraka_biome_1 naraka_biome_0 Snow Music: Hell	The whole layer	None	None

Other dimensions

Outside the locked arenas, a janqualia block portal takes you back to Naraka.

Dimension	How to get in	You arrive at	World	Vermin	Music
Pocket Pocket biome	Clonaqualia block portal.	Y 17	Kept between visits	None	Watery Hill Oasis Meat Factory
Creative Flat biome	Svargaqualia block portal.	Y 1	Kept between visits	None	Abandoned World
Firmament Firmament biome	A Dominion carries you in when it reaches you.	Y 1	Wiped on every entry Hurts outside Y −64 to 512 Snow		Silence
Challenge Challenge biome	A cutscene block that holds the challenge cutscene.	Y 0	Wiped on every entry Hurts outside Y −64 to 512 Portals locked	None	Dream Fight Mindful Killing Salad Slaughter Factory Invasion
YHVH Yhvh biome	A cutscene block that holds the ending cutscene.	Y 1	Wiped on every entry Portals locked	None	Yhvh
Torus Torus biome	Use a covenant ark in Naraka once three different covenants sit on the cells around it. It stays shut in worlds with progression off.	Y 1	Wiped on every entry Portals locked	None	Yttrium
Alma Dungeon Alma biome	Vismruqualia block portal.	Ground near Y 100	Kept between visits	Listed, but nothing spawns here	Yolk
Lucy Lucy biome	Yositaqualia block portal.	Ground near Y 100	Kept between visits Vapor	None	Picked by mood
Debug Debug biome	A portal block, which has no item to place.	Ground near Y 100	Kept between visits	None	Picked by mood

How the loop works

Layers: 30 layers of 256 blocks each, so after 7,680 blocks of Y the same layers come round again.
Which layer: floor((Y + 19) / 256) + 6, counted round the loop. Terrain height moves each border by up to 32 blocks, so layer edges ripple.
Which biome: A biome's share of its layer is its weight divided by the total weight of the layer, rounded down to whole cells of a 32 by 32 grid. The leftover cells go to the layer's first-listed biome.
Sea level: Where a biome has water, it stands 44 blocks above the layer floor, which puts the Surface sea at Y 25. The Underground layer keeps its water 7 blocks higher.
Vermin: Spawns are rolled from the biome's day or night list, and its spawn rate sets how often they appear. Natural spawning runs only in Naraka and Firmament, rare spawns only in Naraka.
First arrival: A new world looks for dry ground from Y 100, which puts you on the Surface layer.

Notes

What a biome carries

Every chunk is filled from the fields of the biome it falls in, listed below.

Field	Value
Building blocks	The solid-ground block list. Some biomes use one block; others mix dirt, grass, and foliage.
Random decorations	Trees, rocks, pillars, mushrooms, houses. Each biome sets its own spawn frequency.
Water decorations	A separate pool for water surfaces.
Structures	Towns, temples, dungeons, pyramids. Each biome carries its own weight for each structure.
Day and night vermin	Two independent spawn pools. Spawn rates sit between 0.0 and 6.0.
Rare chunk chance	How often a chunk in this biome triggers rare placement rules.
Weather	Rain or snow in a few overworld biomes and nothing in most; the ledger above marks each one. Outside the overworld there is a third value: Lucy is the only biome set to `vapor`.

Fixed terrain dimensions

Seven dimensions and the Gallery biome do not use the normal block list. Their terrain is written by the game's native code. The blocks that code places are listed here and on the biome page when they are known. A biome page with nothing under building blocks means they are not known yet.

Dimension / Biome	Terrain blocks
Firmament	Grass, grass foliage, plants, and the janqualia block. The janqualia block doubles as the return portal.
YHVH	Holy ground.
Torus	Holy ground, same as YHVH: the Torus biome is a `YhvhBiome` too, so the same native fill runs for both.
Lucy	Generated by the game from the Lucy biome, which carries no block list.
Challenge	Arena shape comes from the active challenge, not the biome.
Pocket	A single Osmium pillar that pokes out of an infinite ocean.
Creative	Flat plane of Essence Block.
Gallery (Eden)	One random block at every point whose X, Y and Z are all multiples of 8, drawn from the blocks that allow random generation. The layer 6 gallery also lays a floor of essence block on its lower border and holds water up to Y 25.

World limits

Where each dimension ends, and the challenge retry rule.

Field	Value
Horizontal reach	No border. Terrain streams in around you out to 48, 64, 80, or 96 blocks depending on your render distance.
Vertical cycle	Infinite loop. 30 biome layers × 256 blocks = 7,680 blocks per full pass.
Naraka kill plane	None. Falling forever is survivable.
Challenge kill plane	Leaving Y −64 … 512 drains health.
Firmament kill plane	Leaving Y −64 … 512 drains health.
Challenge retries	2 extra attempts per session, added in 2.9.3. A third death ends the challenge.
Side-dimension resets	Challenge, Firmament, YHVH, and Torus forget all world data every visit. Naraka, Pocket, Alma, Lucy, Creative, and Debug persist.