Carceri, The Tarterian Depths

Planar Identity

Carceri is the plane of confinement made permanent. Its world-orbs hold defeated divine powers, political hostages, captured armies, dangerous monsters, deposed monarchs, oath-bound spirits, prisoners of war, wrongfully imprisoned beings and entire societies descended from captives whose original sentences have been forgotten.

Everywhere, freedom has terms. Gates answer to old names, ferrymen demand impossible prices, refuges survive because something remains chained beneath them, and abandoned prisons continue to enforce orders issued by powers dead for millennia. Betrayal flourishes because another person’s captivity is an easy source of leverage.

There is no single Carcerian throne or final court. Gods, outsiders, vanished empires, magical orders and mortal rulers have all built prisons here, and their claims overlap, decay and outlive their creators.

Carceri in Cosmic History

The Astral Plane already links distant realities when Carceri emerges as a destination for enemies too dangerous to reconcile, destroy or release. Over ages, separate systems of exile and containment accumulate across its world-orbs until imprisonment itself becomes the plane’s defining power.

World-Orbs & the Black Gulf

Each layer contains innumerable world-orbs suspended in an immeasurable black gulf. Some hold a single prison fortress; others carry seas, mountains, cities and nations whose inhabitants have never seen another world.

Each orb produces its own gravity. Far from the surface, that pull weakens until a traveller enters the competing field of another world. The crossing passes through a brief region of near-weightlessness before the new world’s gravity takes hold and changes what counts as down.

The gulf is breathable rather than a vacuum, although its air is stale, foul and tainted by nearby worlds. Falling into it does not kill a traveller outright; the greater danger is drifting beyond practical rescue without flight, magic, a vessel or a conjunction route.

Carceri has no conventional sun. World-orbs and planar phenomena cast a dim red radiance across one another.

Conjunctions

A conjunction occurs when two world-orbs, prison systems or planar routes temporarily become accessible to one another. Conjunctions manifest as bridges, root networks, chain-roads, debris fields, gravitational crossings, flooded tunnels and keyed portals.

Some recur predictably enough to support ferry guilds and dynasties. Others happen once and never return.

The Isolation Gradient

Othrys has the greatest concentration of usable crossings. Each deeper layer is harder to navigate: world-orbs stand farther apart, conjunctions are less frequent and reflected red illumination grows weaker.

Custody, Sentence & Authority

Every important prison in Carceri rests on three things: the authority that ordered the confinement, the custodian that controls it now and the mechanism that keeps the captive in place. Those powers often belong to different hands. A sentence can survive its court, a warden can inherit a prison it barely understands, and a release clause can remain valid long after the original conflict is forgotten.

Custodial claims may bind individuals, true names, titles, bloodlines, military companies, offices, communities, objects or supernatural identities. Records, seals, oaths and recognised transfers of authority can therefore matter as much as walls and chains.

Demodand Authority

Stringy demodands, tarry demodands and shaggy demodands are native Carcerian outsiders and the plane’s most persistent wardens, hunters, prison administrators and occupiers. They inherit abandoned fortresses, pursue escapees and fight bitterly over old custodial rights. Some enforce genuine sentences; others forge transfers or turn inherited authority into private power.

Who Comes to Carceri?

Carceri’s population is larger than its prisons. Petitioners gather where a layer’s character echoes the choices that shaped their lives, while living and outsider communities grow around fortresses, ferries, markets, mines and old custodial systems.

Petitioners

The six layers draw different spiritual affinities:

Stronger divine, ancestral or planar claims can draw a soul to another destination.

Prisoners, Exiles & Travellers

Others arrive by sentence, military capture, hostage-taking, exile or deliberate containment. Some inherit ancient custody through bloodline or office; some were imprisoned through fraud or mistaken identity; others lose their route home and become stranded without ever receiving a sentence.

Traders, rescuers, mercenaries, scholars, hags and planar travellers also come voluntarily, supporting settlements that can survive for generations beside active prisons.

Universal Travel & Escape Rules

World-Orb Travel

Travellers cross between world-orbs by flight, temporary bridges, chains, vessels, gravitational crossings, teleportation, conjunctions and specialised planar mounts.

Deep Gates & Crown Gates

These are planar thresholds, not tunnels physically connecting stacked geological strata.

Escape

Carceri resists departure. A traveller without an active custodial claim can leave through valid portals, external anchors, planar magic, conjunctions and other outward routes. A recognised prisoner must also satisfy, break, invalidate or override the claim that holds them.

The Six Layers of Carceri

Select a layer below for its landscape, inhabitants, travel, notable regions, encounters and game rules for 5.5e, Pathfinder First Edition and D&D 3.5e.

Othrys
First LayerCathrys
Second LayerMinethys
Third LayerColothys
Fourth LayerPorphatys
Fifth LayerAgathys
Sixth Layer

First Layer

Othrys — The Ruined Exile

Othrys is the broadest and most frequently reached layer. Stagnant marshes cover many world-orbs, broken by drowned ceremonial roads, eroded uplands, ruined fortresses and palaces occupied by rulers who still behave as though their lost kingdoms exist.

Its characteristic prison is lost authority. A monarch commands thousands of followers, holds court beneath their old banners and still cannot cross an apparently open gate.

Primary Confinement	Lost authority
Environment	Marshes, drowned roads, ruins, broken courts and prison fortresses
Petitioner Affinity	Broken allegiance and betrayal of sworn authority
Principal Prison-Domain	Tartarus
Major Planar Route	River Styx
Native Outsiders	Demodands
Isolation	Lowest of the six layers
Deeper Passage	Deep Gates to Cathrys

Othrys Game Mechanics

5.5ePF1eD&D 3.5e

5.5e Othrys Rules

• Gravity: Normal on world-orbs; unstable around close conjunctions.
• Light: Dim red planar radiance.
• Local Teleportation: Normally functions unless a prison blocks it.
• Escape: A recognised custodial claim must be defeated in addition to reaching an outward route.

Drowning Marshes Levels 1–4

DC 13 Wisdom (Perception or Survival) identifies concealed deep mud. A creature entering it makes a DC 14 Strength save or becomes Restrained and begins sinking. DC 14 Strength (Athletics) frees the creature. A secured rope or pole grants Advantage.

Collapsing Causeway Levels 3–8

DC 15 Investigation or Perception identifies instability. DC 15 Dexterity save or fall 30 feet, taking 3d6 Bludgeoning damage and landing Prone. Failure by 5 or more also leaves the creature Restrained beneath debris.

Tainted Marsh Water Levels 1–10

DC 14 Medicine or Survival identifies unsafe ordinary water. Drinking it requires DC 14 Constitution or Poisoned for 8 hours; failure by 5 or more also adds 1 Exhaustion level. This does not apply to Styx water.

Marsh Gas Levels 5–10

DC 15 Constitution or 3d6 Poison damage and Poisoned for 10 minutes. Flammable pockets explode for 6d6 Fire damage, DC 15 Dexterity half.

Gravitational Shear Levels 7–12

DC 16 Dexterity or pulled 40 feet towards a competing gravity source and knocked Prone. Impact deals 4d6 Bludgeoning damage. A reliable anchor requires DC 14 Strength (Athletics) or Wisdom (Survival).

Conjunction Storm Levels 11–16

Wind: DC 17 Strength or pushed 30 feet and Prone. Red Lightning: DC 17 Dexterity, 8d6 Lightning damage, half on success. Flood Surge: DC 17 Strength or swept 60 feet.

River Styx — Memory Scour

Drinking or significant immersion requires a DC 17 Intelligence saving throw. Failure disrupts recent autobiographical memory for 1 hour and imposes Disadvantage on checks that rely on remembered routes, identities or recent events. Drinking the water, or failing the save by 5 or more while immersed, causes persistent autobiographical amnesia until restored by Greater Restoration or Wish. Languages, proficiencies and class abilities remain intact.

Prison-Seal Discharge Levels 11–16

DC 18 Arcana, Investigation or Religion identifies instability. Three successful DC 18 checks before two failures suppress the seal for 1 hour. A full discharge uses one of the following forms: Force — DC 18 Dexterity, 10d8 Force damage and pushed 30 feet; Fire — DC 18 Dexterity, 10d8 Fire damage plus 2d8 Fire at the start of the target’s next turn; Cold — DC 18 Constitution, 10d8 Cold damage and Restrained in ice; Storm — DC 18 Constitution, 10d8 Lightning damage and Stunned until the end of the target’s next turn; Mind — DC 18 Wisdom, 10d8 Psychic damage and Frightened for 1 minute. A successful save halves the damage and prevents the secondary effect.

Titan-Seal Failure Levels 17–20+

Stage One: 4 successes before 3 failures, DC 19. Stage Two: stabilise three anchors; each requires 2 DC 20 successes before 2 failures. A character who expends a 7th-level-or-higher spell slot on suitable binding or warding magic gains one automatic success. A successful Dispel Magic grants Advantage on the next stabilisation check at that anchor. Stage Three: 5 successes before 3 failures, DC 21. Failure causes a partial breach, manifestation or avatar rather than automatic complete release.

PF1e Othrys Rules

Interplanar escape and layer-changing magic is impeded. A caster attempting such travel makes a concentration check against DC 20 + spell level. Success does not override an independent custodial claim.

Drowning Marshes CR 2

Perception DC 15; Reflex DC 15 or stuck. Strength or Escape Artist DC 15 frees the creature.

Collapsing Causeway CR 4

Perception DC 20; Reflex DC 17 or fall 30 feet for 3d6 damage. Strength or Escape Artist DC 18 frees a pinned creature; Climb DC 15 regains the road.

Tainted Water CR 3

Heal or Survival DC 15; Fortitude DC 15. Effect: 1 Constitution damage and sickened for 1 hour.

Marsh Gas CR 6

Fortitude DC 17 or 1d4 Constitution damage and sickened. Ignition deals 6d6 fire damage; Reflex DC 17 half.

Gravitational Shear CR 10

Reflex DC 18 or pulled 40 feet and knocked prone. Secured creatures gain +4. Climb or Survival DC 15 establishes an anchor.

Conjunction Storm CR 14

Wind: Treat as severe wind. Exposed creatures must succeed on a DC 20 Reflex save every 10 minutes or be moved 30 feet and knocked prone.

Red Lightning: Once every 10 minutes, lightning strikes a metal-bearing creature and all creatures within 10 feet, dealing 8d6 electricity damage; Reflex DC 20 half.

Flood Surge: Strength or Swim DC 20 avoids being swept 60 feet. Failure by 5 or more leaves the creature pinned beneath debris; Strength or Escape Artist DC 20 frees it.

River Styx — Memory Scour

Will DC 20 following significant contact. Failure imposes –4 on Knowledge and Survival checks dependent upon recent memory for 1d6 hours. Severe immersion or drinking causes persistent autobiographical amnesia until removed by heal, greater restoration, miracle, wish or equivalent magic.

Prison-Seal Discharge CR 16

Perception or Spellcraft DC 28 identifies it. Three DC 28 successes before two failures suppress it. Full discharge: 10d8 damage; appropriate save DC 22 half.

Titan-Seal Failure CR 20+

Stage One: 4 DC 30 successes before 3 failures. Stage Two: each of three anchors requires 2 DC 32 successes before 2 failures. Dispel Magic grants +4 on the next stabilisation check. Stage Three: 5 DC 34 successes before 3 failures.

D&D 3.5e Othrys Rules

Interplanar escape and layer-changing effects require a Spellcraft check, DC 20 + spell level. Success does not invalidate a separate sentence or seal.

Drowning Marshes CR 2

Spot or Survival DC 15; Reflex DC 15 or stuck. Strength or Escape Artist DC 15 frees the creature.

Collapsing Causeway CR 4

Search or Spot DC 20; Reflex DC 17 or fall 30 feet for 3d6 damage. Climb DC 15 returns to the surviving road.

Tainted Water CR 3

Heal or Survival DC 15 identifies unsafe ordinary marsh water. Fortitude DC 15; effect 1 Constitution damage and sickened for 1 hour. Styx water uses the separate Memory Scour rule.

Marsh Gas CR 6

Spot or Survival DC 20 detects warning signs. Fortitude DC 17 or take 1d4 Constitution damage and become sickened for 10 minutes. An open flame ignites a flammable pocket for 6d6 fire damage; Reflex DC 17 half.

Gravitational Shear CR 10

Reflex DC 18 or pulled 40 feet and knocked prone. Use Rope or Climb DC 15 establishes a reliable anchor.

Conjunction Storm CR 14

Wind: Treat as severe wind. Exposed creatures must succeed on a DC 20 Reflex save every 10 minutes or be moved 30 feet and knocked prone.

Red Lightning: Once every 10 minutes, lightning strikes a metal-bearing creature and all creatures within 10 feet, dealing 8d6 electricity damage; Reflex DC 20 half.

Flood Surge: Strength or Swim DC 20 avoids being swept 60 feet. Failure by 5 or more leaves the creature pinned beneath debris; Strength or Escape Artist DC 20 frees it.

River Styx — Memory Scour

Will DC 20 following significant exposure. Failure imposes –4 on Knowledge, Survival, Search and other checks dependent upon recent memory for 1d6 hours. Drinking or severe immersion causes persistent autobiographical amnesia until removed by heal, greater restoration, miracle or wish.

Prison-Seal Discharge CR 16

Search or Spellcraft DC 28; three DC 28 successes before two failures suppress the seal. Full discharge: 10d8 damage; appropriate save DC 22 half.

Titan-Seal Failure CR 20+

Stage One: four DC 30 successes before three failures. Stage Two: each of three anchors requires two DC 32 successes before two failures. Dispel Magic grants +4 to the next check. Stage Three: five DC 34 successes before three failures.

Population & Ecology

Othrys’s drowned courts are never quiet for long. Fiendish dire rats swarm through granaries and barracks, giant leeches cling to flooded cells, and fiendish crocodiles wait beneath broken causeways. Around execution grounds and battlefield ruins, vargouilles descend whenever violence leaves fresh carrion.

Demodands patrol the same roads as wardens and hunters. Along the Styx, hydraggons prowl beneath the ferries while thanadaemons carry passengers between hostile planes.

Travel

Othrys contains relatively frequent world-orb conjunctions, causeways, ferries and gulf crossings. Deep Gates towards Cathrys open in drowned caverns, sinkholes, ruined cellars, buried courts and flooded shafts.

Regions of Othrys

The Drowned Causeways

Ancient roads connect ruined prison districts across black marshes.

The Fallen Courts

Deposed rulers preserve ceremonial states long after losing meaningful sovereignty.

The Marsh of Broken Standards

Military banners preserve fragments of forgotten surrender agreements.

The Hostage Keeps

Fortresses contain heirs and descendants of ancient treaty captives.

The Styx Marshes

The true Styx runs among numerous ordinary black-water channels.

The Red Narrows

Closely approaching world-orbs support bridges, chains and ferries.

The Reed-Crown Refuge

A sanctuary whose survival depends upon an imprisoned being beneath it.

The Last Audience

An ancient bureaucracy whose seals remain recognised by distant prisons.

Tartarus — Hellenic Prison-Domain of Othrys

Tartarus contains the great Hellenic prisons created and reinforced through the conflicts surrounding the Titanomachy.

The Hecatoncheires

Briareus, Cottus and Gyges guard the principal Tartarean prisons as custodians of the Olympian settlement, with authority over the prisons entrusted to them.

Prisoners of Tartarus

Prisoner	Status	Role
Cronus	Confined	Deposed Titan king and centre of the largest prison-court.
Coeus	Confined	Hostile Elder Titan retained under the Olympian settlement.
Crius	Confined	Condemned Elder Titan.
Iapetus	Confined	Condemned Elder Titan.
Menoetius	Confined	Titan-descended power struck down by Zeus.
Typhon	Divine-scale confinement	Enemy of Zeus whose prison resonates with Mount Etna.

Other Hellenic punishments: Sisyphus, Tantalus, Tityos and Pirithous remain under their established underworld punishments. Ixion’s punishment remains unfixed, while Hyperion, Oceanus, Atlas and Enceladus stand outside this Tartarean prisoner group.

The Palace of Cronus

Cronus maintains a colossal prison-court recalling his former kingship. His confinement depends upon divine settlement, wardens and seals rather than physical weakness.

The Lesser Titan Courts

Coeus, Crius and Iapetus occupy separate prison complexes with their own servants, rivalries and responses to the possibility of release.

The Prison of Typhon

Typhon is held within a divine-scale system of crushed mountains, volcanic fissures and storm-filled prison caverns. Mount Etna functions as a Material Plane manifestation and anchor rather than Typhon’s complete prison.

Othrys Encounter Table

d12	Encounter
1	A surrendered company’s standard carries valid but forgotten release terms.
2	Giant leeches infest a flooded cell whose prisoners cannot reach the release mechanism without entering the water.
3	A fiendish crocodile waits motionless beneath a causeway where a drowned gate opens only at low water.
4	A giant dire frog attacks from beneath a drowned roadway while something much larger moves in the reeds.
5	A thanadaemon offers Styx passage and renegotiates once land is out of reach.
6	Hydraggons follow a ferry beneath the Styx.
7	A colony of fiendish dire rats occupies a prison granary whose stores are still legally assigned to a vanished army.
8	A tarry demodand escorts prisoners under disputed transfer papers.
9	A stringy demodand closes a conjunction bridge and demands proof of release.
10	A shaggy demodand protects records proving its own authority fraudulent.
11	A flock of vargouilles and several fiendish ravens descend on an execution yard moments after a prison riot.
12	A fiendish giant crocodile has claimed the only intact causeway across a drowned prison district; giant hissing cockroaches pour from the ruined tollhouse whenever it strikes.

Second Layer

Cathrys — The Living Snare

Cathrys consists of forested and swamp-covered world-orbs where vegetation is abundant but rarely generous. Roots split fortifications, vines close roads and fungal colonies spread through abandoned prison districts.

Its defining prison is dependency. Survival frequently requires food, medicine, shelter or routes controlled by somebody else.

Primary Confinement	Dependency
Environment	Predatory jungle, swamp, fungal reaches and living prison systems
Petitioner Affinity	Destructive appetite and predation
Typical Captives	Dangerous fey, predators, captured outsiders and prison colonies
Isolation	Moderate
Crown Gates	Canopy crowns, giant trees and high ruins towards Othrys
Deep Gates	Root caverns, fungal hollows and drowned sinks towards Minethys

Cathrys Game Mechanics

5.5ePF1eD&D 3.5e

5.5e Cathrys Rules

Entangling Growth Levels 1–5

DC 13 Perception detects the danger. DC 14 Dexterity save or Restrained. DC 14 Athletics or Acrobatics escapes.

Poison-Spore Bloom Levels 5–10

DC 15 Constitution or take 4d6 Poison damage and become Poisoned for 10 minutes. Strong wind disperses the cloud.

Memory Spores Levels 7–12

DC 16 Wisdom or Disadvantage on checks to retrace routes, recall local events or navigate Cathrys for 1 hour.

Root Crush Levels 11–16

DC 17 Dexterity or take 4d8 Bludgeoning damage and become Restrained. Restrained creatures take 2d8 Bludgeoning damage at the start of each turn until escaping with DC 17 Athletics.

PF1e Cathrys Rules

Entangling Growth CR 2

Perception DC 15; Reflex DC 15 or entangled and immobilised. Strength or Escape Artist DC 15 escapes.

Poison-Spore Bloom CR 5

Perception DC 20; Fortitude DC 17 or 1d4 Constitution damage and sickened for 10 minutes.

Memory Spores CR 7

Will DC 18 or –4 on Survival, Knowledge (geography) and route-retracing checks for 1 hour.

Root Crush CR 10

Reflex DC 20 or 4d6 bludgeoning damage and pinned. Strength or Escape Artist DC 20 escapes.

D&D 3.5e Cathrys Rules

Entangling Growth CR 2

Spot DC 15; Reflex DC 15 or entangled. Strength or Escape Artist DC 15 escapes.

Poison-Spore Bloom CR 5

Spot or Survival DC 20; Fortitude DC 17 or 1d4 Constitution damage and sickened.

Memory Spores CR 7

Will DC 18 or –4 on Survival, Knowledge (geography) and route-retracing checks for 1 hour.

Root Crush CR 10

Reflex DC 20 or 4d6 bludgeoning damage and pinned. Strength or Escape Artist DC 20 escapes.

Population & Ecology

Every abandoned prison in Cathrys is eventually swallowed by something living. Fiendish monstrous spiders lace old bridges with webs, fiendish monstrous centipedes vanish into root tunnels, and fiendish dire apes hold ruined compounds high in the canopy. Below them, swamp water, poisonous growth and shifting roots make every cleared path valuable.

Settlements survive by controlling bridges, antidotes and drinkable water. Hags bargain over those necessities, demodands tax them, and the jungle quickly closes behind anyone forced off the recognised routes.

Travel

Living bridges, enormous vines and root systems link Cathrys’s world-orbs. The growth closes routes behind travellers, redirects paths and turns yesterday’s safe crossing into a wall of roots.

Crown Gates towards Othrys favour enormous trees, canopy settlements and high ruins. Deep Gates towards Minethys appear in root caverns, submerged fungal hollows and sinkholes beneath the jungle.

Regions of Cathrys

The Rootbound Warrens

Old prison tunnels continually redirected by living roots.

The Viper Canopy

Settlements occupy elevated branches above dangerous swamp floors.

The Sinking Orchards

Artificial islands produce fruit capable of neutralising local poisons.

The Black-Sap Ferry

A mobile settlement travelling on immense root rafts.

The House of Three Antidotes

A hag market controlling cures and safe routes.

Cathrys Encounter Table

d10	Encounter
1	A Crown Gate has disappeared behind the webs of several fiendish monstrous spiders.
2	A colony of fiendish monstrous centipedes fills a root tunnel beneath an abandoned prison.
3	A fiendish dire ape has claimed a ruined watch-fort and attacks anything entering its canopy territory.
4	A green hag and an annis hag control the only antidote after a major spore bloom, each demanding a different price.
5	Giant leeches infest the warm cistern feeding three rival prison settlements while a fiendish crocodile hunts the overflow channel.
6	A tarry demodand patrol collects a dependency tithe from communities using a protected water source.
7	Giant slugs have consumed the fungus supporting a living root bridge, and the crossing is beginning to collapse beneath the traffic.
8	A fiendish giant crocodile has occupied a flooded Deep Gate chamber beneath the Sinking Orchards.
9	A giant wasp nest fills an abandoned watchtower whose roof contains a still-active Crown Gate seal.
10	A fiendish giant constrictor has wrapped itself around a living root bridge while fiendish vipers gather in the branches above it.

Third Layer

Minethys — The Burying Sands

Minethys is a desert of red dust, iron-coloured dunes and abrasive winds. Cities, records and entire prison complexes periodically disappear beneath the sand and re-emerge generations later.

Its characteristic prison is erasure.

Primary Confinement	Erasure
Environment	Red desert, iron dunes, dust storms and buried cities
Petitioner Affinity	Betrayal of duty or responsibility for personal gain
Typical Captives	Erased political enemies, corrupt custodians, mercenaries and lost armies
Isolation	Moderate–High
Crown Gates	Exposed spires and dune summits towards Cathrys
Deep Gates	Buried vaults and fissures towards Colothys

Minethys Game Mechanics

5.5ePF1eD&D 3.5e

5.5e Minethys Rules

Abrasive Dust Levels 1–5

After an hour of exposed travel, DC 13 Constitution or take 1d6 Slashing damage and suffer Disadvantage on the next Perception check before a Short Rest.

Burying Sand Levels 3–8

DC 15 Perception detects instability. DC 15 Dexterity or Strength or become Restrained. DC 15 Athletics frees the creature.

Erasure Storm Levels 5–10

Exposed ordinary maps, painted marks and inscriptions are progressively destroyed. DC 15 Survival each hour is required to maintain a route.

Iron Wind Levels 11–16

DC 17 Dexterity every 10 minutes or take 6d6 Slashing damage and be pushed 20 feet. Success halves damage and prevents movement.

PF1e Minethys Rules

Abrasive Dust CR 2

Fortitude DC 14 after an hour of exposure or 1d6 damage and –2 Perception for 1 hour.

Burying Sand CR 4

Perception DC 20; Reflex DC 17 or stuck. Strength or Escape Artist DC 17 escapes.

Erasure Storm CR 7

Survival DC 20 each hour to maintain the route. Exposed nonmagical records are gradually destroyed.

Iron Wind CR 12

Reflex DC 21 every 10 minutes or 6d6 slashing damage and moved 20 feet; success halves damage.

D&D 3.5e Minethys Rules

Abrasive Dust CR 2

Fortitude DC 14 or 1d6 damage and –2 on Spot checks for 1 hour.

Burying Sand CR 4

Search or Spot DC 20; Reflex DC 17 or stuck. Strength or Escape Artist DC 17 escapes.

Erasure Storm CR 7

Survival DC 20 each hour to retain the route. Exposed mundane records and marks disappear.

Iron Wind CR 12

Reflex DC 21 every 10 minutes; 6d6 slashing damage and moved 20 feet on failure.

Population & Ecology

Life in Minethys gathers wherever broken walls offer shelter from the iron wind. Fiendish giant scorpions bury themselves beneath exposed masonry, while vargouilles follow caravans, battlefields and mass graves newly uncovered by the dunes.

Buried granaries, sealed cisterns and forgotten menageries can preserve whole pockets of danger for centuries. When a storm strips away the sand, old prison roads may reappear already occupied.

Travel

Minethys destroys route knowledge as efficiently as it destroys equipment. Conjunctions remain open while storms erase every surface marker leading to them, leaving intact passages effectively lost in an hour.

Crown Gates towards Cathrys occur around exposed towers, dune summits and temporarily uncovered ruins. Deep Gates towards Colothys open beneath buried cities, inside desert fissures and at the bottom of excavated prison shafts.

Regions of Minethys

The Buried Registry

An archive-city containing old sentences, prisoner lists and release clauses.

The Glasswind Expanse

A plain where storms polish stone and erase exposed inscriptions.

The Moving Cairns

Navigation stones migrate with the dunes and changing gravity.

The Wells of Names

Deep shafts carrying names carved by prisoners determined not to disappear from history.

The City Without Accusers

A prison state whose sentences survived while its judges and witnesses vanished.

Minethys Encounter Table

d10	Encounter
1	A dust squall uncovers a road whose milestones have lost every place-name.
2	A fiendish giant scorpion has burrowed into a newly exposed custody archive and attacks anyone disturbing the stone.
3	A giant scorpion nest occupies a buried caravan whose documents identify its passengers as political hostages.
4	A flock of vargouilles circles a mass grave exposed by the retreating dunes.
5	Two achaierai escaped from a demodand menagerie and now hunt the road between two prison states.
6	An erasure storm uncovers the Buried Registry while simultaneously destroying the route back.
7	An infestation of giant hissing cockroaches pours from a newly exposed prison granary, revealing a sealed stair beneath the stores.
8	A stringy demodand excavation crew has uncovered a prison whose sentence records name the excavators as future inmates.
9	A pair of fiendish giant scorpions shelters in the lee of a custody monument as an iron wind begins.
10	An achaierai hunting pack drives fugitives towards a field of buried giant scorpions.

Fourth Layer

Colothys — The Endless Ascent

Colothys consists of mountainous world-orbs dominated by sheer cliffs, tilted plateaus, ravines and enormous natural arches. Settlements cling to ledges or hang beneath bridges.

Its prison is exhaustion. Freedom remains visibly close while every route demands another climb, bridge, toll or dangerous gravity shift.

Primary Confinement	Exhaustion
Environment	Cliffs, mountains, chasms and vertical settlements
Petitioner Affinity	Destructive deception, fraud and betrayal of trust
Typical Captives	Spies, false envoys, messengers, flying outsiders and labour prisoners
Isolation	High
Crown Gates	Highest peaks and airborne fortresses towards Minethys
Deep Gates	Deep chasms and mountain caverns towards Porphatys

Colothys Game Mechanics

5.5ePF1eD&D 3.5e

5.5e Colothys Rules

Precarious Traverse Levels 1–5

DC 13 Athletics or Acrobatics to negotiate an exposed ledge or broken bridge. Failure by 5 or more normally results in a 30–50 foot fall.

Relentless Gale Levels 3–8

DC 14 Strength or pushed 20 feet and knocked Prone.

Rockfall Levels 5–10

DC 15 Perception gives 1 round of warning. DC 15 Dexterity or take 6d6 Bludgeoning damage and fall Prone; success halves damage.

Gravity Turn Levels 11–16

Loose objects rise 1 round before the shift. DC 17 Dexterity or be hurled up to 60 feet towards the newly dominant gravity surface.

PF1e Colothys Rules

Precarious Traverse CR 2

Acrobatics or Climb DC 15. Failure by 5 or more normally causes a 30–50 foot fall.

Relentless Gale CR 4

Reflex DC 17 or moved 20 feet and knocked prone. Secured creatures gain +4.

Rockfall CR 7

Perception DC 20; Reflex DC 18. Failure: 6d6 bludgeoning damage and prone.

Gravity Turn CR 12

Reflex DC 21 or hurled up to 60 feet towards the new gravity surface.

D&D 3.5e Colothys Rules

Precarious Traverse CR 2

Balance or Climb DC 15. Failure by 5 or more normally causes a 30–50 foot fall.

Relentless Gale CR 4

Reflex DC 17 or moved 20 feet and knocked prone. A secured creature gains +4.

Rockfall CR 7

Spot DC 20; Reflex DC 18. Failure: 6d6 bludgeoning damage and prone.

Gravity Turn CR 12

Reflex DC 21 or hurled up to 60 feet towards the new gravity surface.

Population & Ecology

Colothys belongs to creatures that can cling, roost or fly. Fiendish dire bats fill cliff caves and abandoned lift shafts, while vargouilles circle execution ledges and hanging prisons. Their cries carry for miles across the ravines.

Demodand patrols hold the reliable bridges and landing places. Above them, escaped mounts and flying prisoners move freely from ledge to ledge yet remain trapped by the far harder problem of finding a Crown Gate.

Travel

Travel is dominated by climbing, flight, bridges, lifts and gravitational transfer.

Crown Gates towards Minethys favour mountain peaks, aerial fortresses and summit gates. Deep Gates towards Porphatys open at the lowest points of ravines, cave networks and seemingly bottomless chasms.

Regions of Colothys

The Hanging Ward

A prison-town suspended above a vast chasm.

The Knife Bridges

Narrow ridges controlling access between isolated settlements.

The Ashen Stair

A monumental stair controlled by successive rival factions.

The Empty Summit

A gatehouse whose portal appears only when the correct prisoner arrives.

The Warden’s Rebellion

Demodand fortresses repeatedly change rulers while their prison systems endure.

Colothys Encounter Table

d10	Encounter
1	Exiles reach a ledge too narrow for everybody to camp safely while fiendish ravens gather overhead.
2	A bridge remains connected to another world-orb only while a short conjunction lasts, and vargouilles are already crossing from the far side.
3	A colony of fiendish dire bats roosts inside the counterweight chamber of the only functioning lift.
4	A demodand checkpoint controls a bridge and demands custody papers from every traveller.
5	Gravity changes halfway through a vertical settlement, scattering a flock of fiendish ravens and turning floors into walls.
6	Vargouilles swarm around a hanging prison after an execution platform collapses.
7	A riderless cauchemar, still trailing broken custody chains, circles a mobile fortress drifting between world-orbs.
8	An escaped shadow demon hides in the lightless face of a cliff beside the only route to a Crown Gate.
9	A flock of fiendish ravens has stolen the brass seals from a hanging archive and scattered them across inaccessible ledges.
10	A vargouille swarm and a colony of fiendish dire bats contest the same cavern while a prison lift passes directly through it.

Fifth Layer

Porphatys — The Drowning Dark

Porphatys is dominated by shallow black seas, corrosive precipitation, sleet, wreckage and isolated masses of rapidly eroding stone.

Its characteristic prison is erosion: boats, walls, records, equipment and physical strength gradually disappear.

Primary Confinement	Erosion
Environment	Corrosive black seas, sleet, fog, wrecks and eroding islands
Petitioner Affinity	Abandonment of wider social obligation
Typical Captives	Naval prisoners, aquatic outsiders, prison fleets and marooned armies
Isolation	Very High
Crown Gates	Towers, masts and sea cliffs towards Colothys
Deep Gates	Submerged trenches and drowned vaults towards Agathys

Porphatys Game Mechanics

5.5ePF1eD&D 3.5e

5.5e Porphatys Rules

Corrosive Water Levels 1–5

Full immersion deals 2d6 Acid damage at the start of each turn. Extended wading requires DC 13 Constitution every 10 minutes or 2d6 Acid damage.

Black Sleet Levels 1–8

After each hour without adequate protection, DC 14 Constitution or gain 1 Exhaustion level.

Tidal Surge Levels 5–10

DC 15 Perception gives 1 round of warning. DC 15 Strength or be swept 60 feet and knocked Prone.

Corrosive Storm Levels 11–16

Every 10 minutes, DC 17 Dexterity or take 6d6 Acid damage; success halves damage. Solid shelter prevents exposure.

PF1e Porphatys Rules

Corrosive Water CR 2

Full immersion deals 2d6 acid damage each round. Extended wading: Fortitude DC 14 every 10 minutes or 2d6 acid damage.

Black Sleet CR 3

Fortitude DC 15 each hour or take 1d6 nonlethal cold damage and become fatigued.

Tidal Surge CR 7

Perception DC 20; Strength or Swim DC 18 or swept 60 feet and knocked prone.

Corrosive Storm CR 12

Reflex DC 21 every 10 minutes; 6d6 acid damage on failure, half on success.

D&D 3.5e Porphatys Rules

Corrosive Water CR 2

Full immersion deals 2d6 acid damage each round. Extended wading requires Fortitude DC 14.

Black Sleet CR 3

Fortitude DC 15 each hour or take 1d6 nonlethal cold damage and become fatigued.

Tidal Surge CR 7

Spot DC 20; Strength or Swim DC 18 or swept 60 feet and knocked prone.

Corrosive Storm CR 12

Reflex DC 21 every 10 minutes; 6d6 acid damage on failure, half on success.

Population & Ecology

Wrecks in Porphatys become reefs, lairs and fortresses before the water finally eats them away. Fiendish octopuses coil through chained hulls and flooded cells, while fiendish sharks patrol the deeper, more stable sea-lanes.

Dry shelter and usable water are worth fighting over. Sea hags, prison crews and demodand ferrymen build their power around pumps, breakwaters and the few crossings that survive the corrosive tides.

Travel

Boats, prison barges, debris islands and submerged conjunctions dominate movement. Equipment deterioration makes long journeys increasingly difficult.

Crown Gates towards Colothys appear in tall towers, masts, sea cliffs and storm-borne structures. Deep Gates towards Agathys lie in drowned vaults, submerged trenches and abyssal-looking sea fissures.

Regions of Porphatys

The Weeping Isles

Inhabited islands whose foundations dissolve faster than rebuilding efforts replace them.

The Sunken Registry

A flooded archive containing waterproof prison records and keys.

The Tower of Last Breath

A prison kept habitable only by pumps maintained by its inmates.

The Breakwater of Chains

A harbour formed from immense prison chains and trapped wreckage.

The Drowned Conjunction

A layer-route that opens beneath the corrosive sea.

Porphatys Encounter Table

d10	Encounter
1	Black fog conceals a submerged stone road through corrosive shallows while something large moves beneath the surface.
2	A fiendish octopus has wrapped itself around a half-submerged prison barge and uses the wreck as a lair.
3	A tangle of dire lampreys blocks the pumping channel keeping a prison tower habitable.
4	A sea hag offers dry shelter in exchange for ownership of all recovered salvage.
5	A fiendish shark patrols a stable basin used by smugglers and prison crews.
6	A tarry demodand crew escorts prisoners across a causeway dissolving beneath them.
7	A fiendish dire shark circles the submerged mouth of a Deep Gate as the conjunction begins to open.
8	A prison fleet attempts to monopolise a newly opened conjunction while fiendish octopuses climb the chained hulls from below.
9	A dire piranha swarm fills a sealed reservoir whose emergency sluice is the only route into a submerged archive.
10	A fiendish octopus and a fiendish shark converge on a wreck carrying still-valid prisoner-transfer seals.

Sixth Layer

Agathys — The Final Stillness

Agathys is the most isolated mapped layer of Carceri. Its world-orbs are covered in black ice, glacial ridges, frozen plains, crevasses and vaults built to preserve captives across immense spans of time.

Its defining prison is suspension.

Agathys is Carceri’s principal deep-storage containment environment. Its deepest vaults hold beings whose release or destruction would cause greater harm, with distance, ice and isolation reinforcing the prison.

Primary Confinement	Suspension
Environment	Black ice, glaciers, crevasses and sealed vaults
Petitioner Affinity	Betrayal of intimate personal bonds
Typical Captives	Immortal monsters, ancient outsiders, primordial fragments and dangerous relics
Isolation	Extreme
Crown Gates	Rare ice spires and restored vault-gates towards Porphatys
Deep Gates	None — Agathys is the sixth layer

Agathys Game Mechanics

5.5ePF1eD&D 3.5e

5.5e Agathys Rules

Extreme Cold All Tiers

After each hour without suitable protection, DC 15 Constitution or gain 1 Exhaustion level. Cold resistance grants Advantage; Cold immunity normally removes the need to save.

Black-Ice Crevasse Levels 1–6

DC 14 Perception detects the concealed crack. DC 15 Dexterity or fall 40 feet, taking 4d6 Bludgeoning plus 2d6 Cold damage.

Frost Storm Levels 5–10

Every 10 minutes, DC 15 Constitution or take 4d6 Cold damage and suffer temporary impairment to Perception.

Suspension Field Levels 11–16

DC 17 Arcana or Religion detects it. DC 17 Constitution or become Restrained for up to 1 minute and lose Reactions until the start of the next turn. Repeat the save at the end of each turn.

PF1e Agathys Rules

Extreme Cold CR varies

Fortitude DC 15 each hour without protection or take 1d6 nonlethal cold damage and become fatigued.

Black-Ice Crevasse CR 3

Perception DC 18; Reflex DC 17 or fall 40 feet for 4d6 falling damage plus 2d6 cold damage.

Frost Storm CR 6

Fortitude DC 18 every 10 minutes or take 4d6 cold damage and –4 Perception for 1 round.

Suspension Field CR 12

Perception or Spellcraft DC 25; Fortitude DC 21 or become entangled and staggered for 1d4 rounds.

D&D 3.5e Agathys Rules

Extreme Cold CR varies

Fortitude DC 15 each hour without protection or take 1d6 nonlethal cold damage and become fatigued.

Black-Ice Crevasse CR 3

Search or Spot DC 18; Reflex DC 17 or fall 40 feet for 4d6 falling damage plus 2d6 cold damage.

Frost Storm CR 6

Fortitude DC 18 every 10 minutes or take 4d6 cold damage and –4 Spot for 1 round.

Suspension Field CR 12

Search or Spellcraft DC 25; Fortitude DC 21 or become entangled and staggered for 1d4 rounds.

Population & Ecology

Most of Agathys appears lifeless until a traveller reaches heat. Around geothermal fissures, prison kitchens and thaw corridors, fiendish polar bears and dire wolverines hunt the narrow margins between shelter and open ice.

Beyond those pockets, the greater danger lies inside the vaults. Demodands patrol functioning containment systems, and ancient outsiders or singular monsters emerge when ice shifts, seals fail or a forgotten prison finally opens.

Travel

Agathys has no deeper recognised Carcerian layer. World-orb conjunctions are exceptionally rare and long distances separate many known prisons.

Crown Gates towards Porphatys open at immense ice spires, exposed glacial summits, restored vault entrances and ancient gates brought back into operation after millennia of disuse.

Regions of Agathys

The Still Vaults

Widely separated prisons whose occupants are held in magical, temporal or physical suspension.

The Name-Fissures

Deep crevasses lined with names visible through translucent ice.

The Ember Refuge

A rare permanent settlement possessing a reliable source of heat.

The Black Mirror Plain

Dark ice reflects distant world-orbs and occasional conjunctions.

The Unopened Gate

A colossal prison gate whose original administrative authority has vanished.

Agathys Encounter Table

d10	Encounter
1	A black-ice crack opens beneath the expedition and reveals architecture far below.
2	A frozen corpse carries a prison key that remains warm despite the cold.
3	A colony of fiendish dire rats occupies a heated archive whose furnace is still running after centuries.
4	A dire wolverine stalks a thaw corridor between two inhabited vaults.
5	A fiendish polar bear has taken over an abandoned provisioning station beside the Ember Refuge.
6	A suspension field expands beyond its intended boundary and begins freezing an inhabited settlement.
7	A colossal silhouette appears beneath the ice, but every surviving seal identifies it differently.
8	A shaggy demodand patrol reaches the Unopened Gate just as it recognises one adventurer as an authorised custodian.
9	An imprisoned shadow demon escapes through a cracked suspension seal and vanishes into the black-ice fissures.
10	Giant hissing cockroaches break through a centuries-old ration wall and expose a forgotten administrative passage beneath the Ember Refuge.

Carceri and the World of 1454

In 1454, knowledge of Carceri reaches Earth through learned natural philosophy, magical scholarship, recovered prison keys, court records, travellers’ testimony and rare surviving accounts of planar journeys.

Mortal knowledge is fragmentary. Hellenic scholars recognise Tartarus and the Styx; reliable descriptions of Cathrys, Porphatys and Agathys survive only in specialist magical archives, travellers’ accounts and recovered prison records.

Material Resonances

• fortresses used for political hostages;
• abandoned prisons containing unresolved sentences;
• sealed mines and underground complexes;
• battlefields where surrender agreements were betrayed;
• castles associated with vanished dynastic prisoners;
• sites where supernatural beings were bound rather than killed;
• river crossings associated with old oaths, exile or supernatural memory-loss;
• ritual gates constructed to exile something too dangerous to remain on Earth.

Such places create strong sympathetic conditions for Carcerian magic, and a small number conceal genuine planar crossings.

Why Enter Carceri?

Rulers commission expeditions to recover heirs and hostages. Universities search for scholars lost through experimental planar travel. Military powers negotiate prisoner exchanges. Magical orders reinforce failing seals before their captives reach Earth.

Other expeditions enter for the opposite reason: to confirm that something ancient remains securely imprisoned.

Using Carceri in Play

Carceri is a plane of difficult freedom. Its prisons have rules, owners, weak points and consequences, so escape is possible when characters learn how a particular confinement actually works.

A prison becomes memorable when its authority, custodian, release condition and hidden beneficiaries pull in different directions. An innocent hostage can be held by a flawless seal; a guilty prisoner can possess a valid release clause; a demodand can enforce an ancient sentence while exploiting everyone around it. Settlements, markets and travelling communities grow in the spaces between those claims, giving Carceri lives and loyalties beyond the cell door.

The strongest journeys through the plane make freedom discoverable and costly. Opening a gate changes who holds power, who remains protected and what the released prisoner is able to do next.

Adventure Hooks

Historic, Mythic & Game Context

Ancient Hellenic Foundation

Ancient Hellenic tradition supplies Carceri’s most famous prison: Tartarus. In Hesiod’s Theogony, Tartarus belongs to the oldest cosmic structure and becomes the place of confinement for defeated hostile Titans. The Library attributed to Apollodorus also preserves Titan imprisonment and the casting of Menoetius into Tartarus.

The River Styx

Hellenic tradition makes Styx one of the great underworld rivers. Later fantasy planar cosmology expands it into a transplanar waterway. In SpiralWorlds the river crosses Othrys and Abaddon, carrying ferries, predators and rare outward routes through otherwise isolated regions.

The Six Layers

Fantasy planar tradition associates Carceri’s six layers with different forms of betrayal and increasing isolation. SpiralWorlds carries those themes into the landscape of each layer, from Othrys’s lost authority and Cathrys’s dependency to Minethys’s erasure, Colothys’s exhaustion, Porphatys’s erosion and Agathys’s suspension.

Carceri in Fantasy Gaming

This video surveys Carceri’s place in fantasy planar lore and provides useful background for the plane’s game-history.

Further SpiralWorlds Reading

• Planes of Existence
• Planar Campaigns
• Astral Plane
• Hellenic Pantheon
• Cronus
• Typhon