Stygia

Stygia’s frozen surface is ever-shifting—floe fields grind against one another, creating crushing walls of ice, while bergs the size of fortresses drift unpredictably. Some floes support entire cities, others hide deadly fissures that collapse underfoot. In certain warmer pockets where geothermal vents melt the ice, swamps of hardy arctic flora flourish, attracting prey and predators alike.   The sky is a perpetual dusk, lit only by distant arcs of lightning that strike down in blinding bolts. Flying creatures risk being hurled from the air, while the deafening thunder rolls unending across the ice, masking the approach of predator and foe alike.  

Notable Locations

Tantlin

The City of Ice, the largest settlement of the layer, built atop a massive drifting floe on the Styx’s banks. Ruled by an enigmatic pit fiend, Tantlin serves as both a trading post and a military port, where frost-armored legions muster on the frozen quays.  

Sheyruushk

The shadowed, fiendish realm of Sekolah, lying beneath the frozen surface. The devout and the damned alike speak of hunting grounds where the shark-god’s chosen prowl among jagged undersea trenches.  

The Tomb of Levistus

A towering iceberg at the heart of Tantlin’s harbor, its cold prison holds the archduke himself. The ice is said to be unmelting, impervious even to Phlegethos’s hellfire.  

The Black Sea

The Styx in full sprawl, pitch-dark water laced with mineral brine and floating shoals of knife-ice.  

Pack-Ice Labyrinths

Miles of wind-sculpted corridors; currents rearrange them nightly.  

Calving Walls

Cathedral-high cliffs that shed bergs with city-leveling shockwaves.  

Drowned Ziggurats

Sunken, silt-choked complexes visible in rare calms, crawling with contract-wights and worse.  

Brimharbor

Also known as the the Floe-Port, a chained flotilla of wrecks and iron platforms. Markets sell soul-collars, memory-anchors, and maps that are always a week out of date.  

The Knife Market

A covered bazaar inside a hollow berg where betrayals are bought and sold—informants, double-crosses, severable clauses.  

Deadwake Armada

A graveyard of frozen ships fused into one drifting fortress; boarding actions never truly end.  

Serpent Trench

Stygia’s deepest channel; the Styx roars here with amnesic mist. Devils drop prisoners to “soften” them before interrogation.  

The Drowned Archive

A library entombed in layered ice, each shelf a century deeper. Extracting a page means thawing a decade.  

Inhabitants

Devilkind in Stygia is a mixture of martial and opportunistic breeds: abishai, amnizus, erinyes, gelugons, and spinagons dominate its ranks, with hamatulas serving as elite wardens. Unlike other layers, pit fiends are rare here. Mortal-blooded agents and even succubi can be found in Levistus’s employ, often serving as spies or intermediaries.   Outside the devil strongholds, the wilderness is ruled by frost giants, krakens, dire wolves, frost worms, remorhazes, polar bears, and massive sharks. Many of these beasts are captured and broken into service for military drills, their savagery redirected into Hell’s wars.   Mortals often reside here as corsairs, smugglers, oathbound debtors and spies who can't safely retire anywhere warmer.  

Government

The frozen dominion of Stygia is ruled by Levistus, the imprisoned archduke, entombed within the glacial monolith known as the Tomb of Levistus in the harbor of Tantlin. Though encased in unyielding ice, Levistus exerts his will through sheer force of mind, his telepathic reach spans leagues, allowing him to direct his agents, command the amnizus under his authority, and weave intrigues across the Hells. His imprisonment has not dulled his ambition; whispers speak of his relentless plotting to usurp control of another layer.  

Access and Travel

Those who travel the Plane, most likely venture with suitable gear, and never tavel alone and most likely use triple-tie lines and carry a fresh-written account of who they are, sealed in pitch. Those who travel without charer and caught by patrol, are assumed to be pirates and acted accordingly.  

From Phlegethos

Fumarole shafts and basalt chimneys descend into glacial caverns that open onto the Stygian sea.  

Toward Malbolge

The far pack-ice rises into grinding pressure ridges and black cliffs patrolled by elite devils.  

Styx Corridors

Chartered ferries (marraenoloths and licensed infernal pilots) navigate fixed “memory lanes” where splashing risk is minimized, at a price.

Stygian Brine

Any immersion (even a splash) risks memory loss as per powerful enchantment, where names, faces, and promises go first.  

Treachery’s Weight

Ice under an oathbreaker spiderwebs and thins; under oath-keepers it thickens and bears.  

Echo-Glass

Clear ice sometimes traps scenes of betrayal; breaking it releases a psychic “echo” (useful intel… or a curse).  

Memory Reflux

The sea sometimes returns a single memory as a vision which is often weaponized by interrogators.  

False Calm

Mirror-flat water that invites landings; the whole sheet flips without warning, crushing or drowning those atop.  

Namefrost

Writing a true name in hoarfrost makes it briefly loud to divinations; escorts use this to guide in whiteouts (and assassins use it to find you).

The vision drops to arm's length and navigation relies on line, bell and luck where many Horizontal bolts arc between bergs. Their impacts flash-freeze exposed flesh and then shatter it.

Brimfrost

Chemical hoarfrost that burns like acid and tastes like old lies.

Some infernal scholars claim that Stygia was not always part of Baator. According to this theory, it was once a mortal world of the Prime Material Plane that faced annihilation. In desperation, its rulers forged a pact with Ashmedai, offering their realm and souls in exchange for deliverance before the cataclysm known as the Planar Divergence. If true, this would explain the abundance of creatures from the Material Plane that survive here, as well as the persistent legends of untouched treasures from that lost world buried beneath the ice.   Others hold that Stygia is the very source of the River Styx, its waters permeating the layer and seeping into every glacier and floe. The Styx here is said to be stronger, more dangerous, and more capable of erasing not just memories but the essence of identity itself.