Stygia

Stygia was the fifth layer of the Nine Hells of Baator. Ruled by the archdevil Levistus, the Frozen Wastes, much like its prince, was a strange part of Hell's hierarchy, fulfilling no explicit function. Instead, the untamed expanse that was the Great Sea was a proving ground, an environment of cruel cold and active conflict that tested the prowess and endurance of infernal soldiers against monstrous beings that did not fear them. Stygia was named after the River Styx, which crisscrossed its entire extent.
==Description==
Stygia was best described as a frigid ocean, a pit of endless, murky seas and unpredictable currents churning with crushing, unimaginably massive ice floes and icebergs. It was a realm where the powers of ice and cold were empowered, while those of fire and heat were diminished (even those from magic items and spells); even light magic was influenced by the plane, taking on a soft, gray radiance. A thick layer of ice covered the layer, pack ice extending up to deep, but in many places it gave way to open water, and even in such a place as Stygia the ice slowly melted, feeding the dark river for which the layer was known.
Strange as it is to consider a river running through an ocean, the Styx wound its way through the Stygian seas, maintaining its own integrity along the way. It meandered across the 5 layer like a winding serpent, just as it would a plain and fast enough that it avoided freezing (although its flow was still sluggish and the layer's cold chilled its fetid waters). Where river met ocean, the oily, putrescent waters of the Styx were clearly distinct from the surrounding sea.
Besides the bitter cold and River Styx, the other connecting theme of Stygia was the bitter, bloody backstabbing of its master, Levistus. Stygia was an uncaring hell, a place that ripped away love and compassion, consumed sorrow and, for some period of time at least, had a pervasive sense of hunger lingering beneath its biting winds. Through the attentive influence of its lord, however, the unreasoning tempest could become like a living thing, a crushing and caressing force that cajoled and commanded. As its will screamed, the ice would quake and crack as geysers of water burst forth from beneath.
Civilization in Stygia was contained to the dominant surface, the ice floes, specifically those large enough to serve as foundations for cities and castles. Communities had a tendency to form by parts of the floes where the Styx cut through, with people clustering near its banks since it wouldn't freeze over and thus provided relatively easy transportation despite its overall toxicity. Several areas in Stygia were connected by bridges of black wrought-iron that arched far into the sky before coming down again some thousands of feet later. Such bridges were caked in frozen algae and slime, ominously trembled when walked upon, and were so slippery that those not crossing carefully were at serious risk of falling into the ocean or ice.
Along the Styx's blighted banks, approximately every , were fortress checkpoints equipped with watchtowers and processing centers. Once identified, visitors would be made to go through the long twisting halls of the gloomy, unwelcoming sites. These were as much mazes of corridors as they were of regulations, though they were equally convoluted in either sense. After waiting in the dark, pungent places, visitors would be interrogated on their intent and possessions, strip searched, and once thoroughly humiliated, made to pay an entrance fee somewhere below 500 gold pieces in coinage, gems, magic items or other valuables.
A great fleet of icebreaker ships were maintained in Stygia to keep its icy channels free from debris, and those trying to make use of cleared routes were heavily taxed. Attempting to sail through Stygia without an icebreaker was likely to leave a ship trapped, crushed, or capsized by the ice, and the crew easy prey for scavengers and opportunists. However, piracy was not tolerated in Stygia under Levistus's regime, and hunter ships consisting of his most crude and cunning servants stalked the water, sometimes even posing as distressed themselves, ready to ambush any would be raiders. Many ships plied even the remoter seas of Stygia under the direction of Levistus's devils and other agents.
===Geography===
The Stygian landscape consisted of many rises and falls. Much of it was high, such as the endless, tumbled mountains of ice and frozen rock. There were also long, twisting, rocky canyons and hanging valleys, and even a few volcanic rifts in the mountains called steam trenches. The treacherous alpine and glacial ice made scaling Stygia without the aid of magic like spider climb difficult, not to mention that avalanches were common. Though its terrain was rugged, Stygia was rich in natural wealth. The mountain quarries yielded much of the structural stone used throughout the Hells, including granite, basalt, marble, and even chalk, as well as rubies, beryls, and turquoise from seams and veins. Meanwhile, many igneous, metallic ores could be found in the stream trenches high in the outlands.
Closer towards the center of Stygia, the encircling mountains were left behind in favor of a vast salt swamp which filled much of the layer. Contrary to what the word swamp might imply, the Stygian swamp was still a frozen place, although one with an interesting explanation. For eons, tiny arctic plants and mosses took root in Stygia's thick ice, sending tendrils deep inside it to gather what little nutrients there were, and the millennia of decay underwent by such plants created cold swamps atop the pack ice. The areas of thickest swamp were the most hospitable, although naturally this meant they were the places a wide variety of other creatures found more comfortable. Furthermore, these were also the places the layer was the warmest, and the dangers of falling through the ice were exponentially higher there.
The frozen white landscape of Stygia juxtaposed the black waters of its lightless seas and the Styx. Intriguingly, while the Styx remained fluid by moving fast enough to not completely ice over (though there were still icebergs choking its flow), it was unclear why the swamp did not. Notably, the spell transmute water to dust worked on the swamp waters of the upper hell of Minauros, but not on the Styx itself or the salty waters of Stygia's swamps and ocean. The Styx's waters fell from the mountains and swelled into the swamp, and from the river's bottom, opals and topaz could be dredged up.
There was no sun in the Stygia, just a gloomy sky filled with smoky black clouds and a landscape of eternal twilight dimmed by the long shadows cast by great icebergs. Rather, the fifth layer was illuminated by the constant flashing of lightning, although that might be an overstatement since one could only see up to away. Regardless, electrical storms in Stygia were common to the point of being ubiquitous; there was no break in the the lightning, and following every bolt was thunder, creating a steady, subdued, ever-distant roar that echoed across the icy plains. Other noteworthy qualities included the sharp stench of frozen-over ordure sometimes in the air and the shooting stars of smoking ice that sometimes hurtled across the sky from the peaks and plunged deep into the swamp.
===Cold===
It was obvious enough that Stygia was cold, cold enough that long-term exposure to its barren environment of perpetually blowing sleet and snow was dangerous, and even worse if one entered the frigid water. But the cold of Stygia was also supernaturally dangerous. For example there were the cold fires, weird white flames that were horribly freezing to the touch. They burned on rocky peaks where lightning struck for some time, although it was unclear what was fueling them given that they seemingly blazed on bare rock and left no trace on it or the ice.
Stygia was also the source of Stygian ice, an extraplanar form of ice infused with the plane's soulless evil and the waters of the Styx. The black substance constantly crawled with a thin layer of pale blue mist, was colder than normal ice (though it still melted if in an area above , albeit slowly) and when melted gave off nauseating vapors. But what made Stygian ice particularly deadly was not what it did to the body, but its faster effect on the mind. Those making contact suffered its magic, freezing cold and had their memories slowly frozen. Further contact brought physical debilitation that ended with the victim rising as a wraith in a under a minute.
The drawbacks of weaponing the ice was that it was somewhat fragile, being only slightly harder than normal ice, and could be destroyed with flame, especially magical flame. Furthermore, unless wielded with extreme finesse or by one immune to the cold, it would inflict the same torments on its wielder as it would their opponent.
==Cosmography==
By Asmodeus's decree, no planar portals could connect directly to any layer of Hell besides Avernus. This meant that in general, if one wanted to get to Stygia they would have to go the layer above it, Phlegethos, and find a portal, and likewise would need another to get to Malbolge below. Portals existed from the only city in Phlegethos, Abriymoch, to Tantlin in Stygia, as well as from the City of Ice to at least one of the many copper fortresses in Malbolge from the Moloch regime. Balls of cold fire danced about the barrier regions to the Hells above, and if one traveled deep enough down (somewhere beyond ) it was possible to enter the "neither-here-nor-there realm" betwixt Stygia and Malbolge, where the cold would recede.
It was also possible to reach Tantlin from the divine realm of Ankhwugaht also in Stygia. Interestingly, the bitter cold in Material Plane locations that become as frigid as Stygia, such as what Icewind Dale almost became under Auril's Everlasting Rime, allows Levistus to open portals between said places and Baator.
===River Styx===
Stygia was varyingly described as the headwaters and culmination of the River Styx. The river never seemed to actually go anywhere, for while its waters rushed in consistent directions on any given plane (never emptying nor flooding its banks) its course was inconsistent across the planes. The river fell from the mountains of the Frozen Wastes, slowing as it ended in the Stygian swamp and sea, only for the merrenoloths (the infamous daemonic boatmen of the river) to take their skiffs through the swamp and pass on to other planes without having to climb back out through the mountains.
Regardless of if it was the beginning or the end, Stygia's relation to the Styx was unique. Not only did the Styx clear a channel there, which normally only occurred on the top layers of the lower planes, but it ran through Stygia both ways, containing both an entrance and exit. From Stygia's waters, already befouled with detritus and flotsam, the river grew progressively more polluted as it made its way through the other lower planes, picking up more debris as it went, until coming back into Stygia and depositing the new filth on the layer's icebergs.
By some accounts the river Styx had been diluted in Stygia, which reduced the river's memory-robbing influence, while in others it was the reverse, and the entire layer's water supply was toxic (although melted ice from the bergs would not induce the Styx's amnesiac effects). Regardless, the waters of the Styx were, in truth, particularly potent and concentrated in Stygia. 
===World Axis===
In the World Axis cosmology model, the Nine Hells were a planet-shaped astral dominion floating in the Astral Sea, no longer of infinite size nor consisting of layers. In this cosmology Stygia was a vast, dark, icy cavern about across and a few miles high, one supported by a handful of mountainous columns that rose like islands from the layer's oceans. The frozen sea was dotted with jagged, towering icebergs, and dimly lit by the faint auroras of green-blue frostfire that flickered in the upper reaches of the cavern and cast long shadows across the landscape.
Stygia sat about as deep within Hell's sphere as the upper layer of Phlegethos, but was hundreds of miles away, underlying the 2 layer of Dis instead due to the twists and turns of the plane's caverns. It was connected to its technically neighboring Hell by way of the Road of Cinders, a torturous, broken maze of lava tubes and rifts which grew colder and darker until one finally left the heat of Phlegethos for the cold of the Stygian shores. There were also a path of dismal, miles-long, ice-coated, iron stairs hidden in one of Stygia’s mountain-columns that connected Stygia and Dis. 
At Stygia's farther shore, several long, icebound canals led off into the darkness, going hundreds of miles from Stygia to the cavern of Malbolge. As the canal thawed it flowed into one of the former ruler's fetid open veins, a passage lined with great, colorful blossoms with intoxicating scents, as if Glasya meant to draw the differences of her and Levistus's domains into sharp contrasts.
In the World Axis, the Styx slowly and sluggishly wandered from Minauros to Stygia, taking a long, dark journey to the icy sea that included a precipitous plunge. Curiously, there were also several well-guarded, icy portals adrift in the sea near Tantlin that linked Stygia to various parts of the Material Plane.
==Notable Locations==
* Tantlin, the City of Ice, a translucent settlement created from carved ice and shaped then frozen water. It was the greatest, largest city in Stygia and lied at the center of the plane, occupying the vastest of the plane's icebergs. The city was an important trading point despite its location deep in the Hells, second only to the city of Dis in terms of traffic into the infernal realms due to its closeness to the Styx. Higher ranking devils could be found deep within its concentric structure, while visitors and lowlier fiends were consigned to the fringes.
* Citadel Coldsteel, a sprawling fortress complex secretly designed and built by Geryon to capture a temple Asmodeus forewarned him would magically appear beneath Stygia, in the hopes he would be returned to power. Its diabolical architect fashioned it almost entirely out of well-crafted steel, making it appear almost clinically clean, although due to having been built inside an iceberg, it was inhospitably cold, even by most infernal standards. It was designed to be hidden, with only the iceberg's tip peaking out of the surface and the only entrances underwater, but reports after Geryon lost and reclaimed it described it as rising from the ice at the center of Stygia. Within a mile of the citadel howling winds and screams filled the air, keeping many from sleeping properly, and shimmering portals frequently appeared seemingly leading to places considered safe to their onlookers, only to deposit them elsewhere in Stygia.
* Duelist's Chasm, a jagged fissure in the vast iceberg of Ghiskidin, carved out to house a circular ground slick with a permanent red slush formed from previous fighters' semi-frozen gore. The paying audience sat within boxes incised into the fissure's sides, traversed by frayed rope ladders and visited by barbazu gambling masters taking bets and shouting odds to their amnizu bosses on the chasm’s lip. In few other places could devils commit violence against each other outside of great or clear outrankings. After filing the paperwork and waiting four to six weeks for processing, applicants would receive a License of Lawful Combat. Such permission was unneeded to fight non-devils, but even they might be invited there; besides settling differences, chasm combat was a chance for fame, glory, and profit.
* The Hall of the Vanquished, a combination museum and training ground consisting of a series of interconnected display rooms carved into the Stygian ice. Bound within were the mightiest foes slain by Levistan cultists - including famous heroes, archons, demons, chaos beasts, and other typical baatezu opponent - diverted from their proper afterlife through the bind to Hell spell. The figures stood frozen, posing dramatically on pedestals before information plaques carved in unquenchable fire on slabs of ice that described each subject's capabilities, legendary deeds, and how to combat similar entities. Devils and cultists could apply to have specimens temporarily thawed for training purposes, and occasionally the friends of captured mortals staged raids and sometimes succeeded in freeing specimens despite the traps and guards. Escape was only possible once outside the hall, else the subject would simply return to their pedestal with a new tortured expression.
* The Pillar of Geryon, a crude, humanoid-shaped block of granite (about high, wide and thick) jammed into the slow-moving glacier Elgarz. The forgotten monument to Stygia's former ruler grinded slowly through Stygia, although it never came within of Levistus's Tomb. Simplistically carved into its surface, similar to a cave painting, was a full-body outline of Geryon with deep depressions where the right hand and head should be, and eroded steps jutted out from the pillar's base allowing access to those areas. Placing one's left hand in the hand depression severed the wrist before the amputation was slowly regenerated as a gnarled, rubbery, olive-green, slightly larger new hand covered in pulsing scar tissue, which gradually found weakness in enemy armor and was effective against the powers of chaos and good. After ninety-nine days acts of law or evil were needed to renew its powers (if not its presence), and despite the legends, sacrificing one's head just ended in decapitation. 
===Divine Realms===
* Ankhwugaht, the divine realm of Set, a burning hot desert that stood in stark contrast to the surrounding frozen landscape despite sharing its similarly twilit sky and glaciated soil. The land was covered in monuments and interconnected by catacombs all celebrating death over life and Set over other deities. From his great black pyramid in the center of the realm he could gaze upon his entire domain and plotted for dominance over the multiverse.
* Sheyruushk, the divine realm of Sekolah, an aquatic realm miles beneath the frozen surface of Stygia. Accessible from a valley formed by two icebergs close to Tantlin (if not without teleportation), here the shark god glid attended by fiendish sahuagin. Frequently Sekolah, sahuagin, and the multitude of sharks from his realm set out to raid and hunt in the many waters of Stygia, leaving the realm itself behind when they went. 
==Inhabitants==
The primary inhabitant of Stygia was Levistus, sealed away in his tomb. He ruled the layer directly through telepathy, issuing commands and gathering information with perfect awareness even while immobile. However, there was also its previous ruler, Geryon, to consider. The Wild Beast's ferocity served him well in the Frozen Waste, but it limited his ability to forge an effective hierarchy as he marshalled his followers to unseat his hated rival.
The fiefs of Stygia's dukes were located in the iceberg canyons and valleys of the Frozen Waste, sitting between the primary city of Tantlin and the plane's swamps and the rocky mountain regions. For a time Levistus seemingly secured the services of Amon the Wolf, who he relied upon to sniff out the schemes of his enemies in Stygia, although given that duke's hatred of both Levistus and treachery in general, and the later confirmed existence of a pit fiend seneschal and general by the name of Amon, the truth of the matter was uncertain.
Of the old guard of Geryon's regime, only two remained under Levistus's dominion. One was Machalas, the least of Geryon's dukes in both personal power and influence, and Agares, an opportunistic and unsatisfied fiend Levistus warily regranted control over 31 devil legions, as well as Stygia's eastern extent. Curiously, he was a loyal servant of Geryon but constantly frustrated by his ancient enemy Amon, who he perceived as duplicitous despite the Wolf's hatred of such things. He had fed lies to Asmodeus's agents about both Amon and Geryon in hopes of prompting his intercession, which ultimately only served to help instigate the Reckoning and see the two exiled. Though he emerged from the conflict with his power expanded, and Levistus was short of dukes, many suspected that his days were numbered.
Garrisoned on Stygia were the Stygian Champions, called upon by Warlord Bel whenever the numbers of the demonic host leveled against the armies of Avernus became insurmountable by ordinary means. This legion of Levistus was led by the Dark Eight pit fiend Baalzephon and heedless, swashbuckling commanders who specialized in mobility, maneuverability, and turning the numbers of their enemies against them.
===Devils===
Stygia was a realm wracked by war where lesser devils were sent to have their martial skills sharpened, their endurance increased, and their abilities assessed by their commanders so they could be assigned in appropriate legions when the time came for them to report to Blood War duty in Avernus. Devils bound to Levistus or Geryon not needed for that conflict engaged in combat regardless in the form of constant skirmishes against the other archdevil's forces, though when Levistus's dukes needed to keep their armies occupied they had them construct the bridges that connected the plane's icebergs.
Most devils avoided Stygia, its bitterly cold seas able to quench even their infernal fires. They considered Stygia's icebound cities normal environments, but even for them there were some areas unwelcoming in temperature. Even so, time on the glacier made Levistus's Stygia-based servants accustomed to inhospitable ice and chill and taught them how to use the environment to their advantage. They could move and fight freely on the ice just as they could a solid, less slippery surface, and could even harness the Stygian cold when striking their enemies. Most devils could also survive and resist the Styx waters, but its touch was still dangerous, and full submergence risked legions of lesser baatezu turning into hordes of confused amnesiacs.
Stygia's devil population was unique in that pit fiends were not truly supreme there. Already rare in the middling Hells, they gave the cold lands of Stygia in particular a wide berth. Rather, it was the amnizus, the styx devils, who ruled the roost in Stygia, acting as Levistus's most trusted chancellors and sycophants. Levistus gave them many important tasks and went so far as to tell them they were above Hell's laws, making them arrogant and believe themselves outside the baatezu hierarchy. As such, the already treacherous devils were particularly untrustworthy when it came to pit fiends, and even routinely subverted and outright defied the Dark Eight to advance Levistus's agenda, all part of the archdevil's plan to tip the balance of ruling support and expand his power.
Stygia was the primary dwelling of the amnizu, and the city of Tantlin held the greatest concentration of their kind. It was they who ruled almost every city, and their responsibility, as the Keepers of the Styx, to defend Stygia, namely by stopping invasion attempts through the River Styx. They manned the watchtowers, fortresses and processing centers along its banks They were also generals, each often commanding an army of thousands of abishai (notably white abishai) and erinyes devils in service to Stygia's protection. But while they performed their duties admirably, they turned their armies to serve their own ends, and perhaps sought to break out of their guardian status to show baatezu-kind that their rank, in respect at the very least, was equal to that of the pit fiends.
As for the other diabolic denizens of Stygia, one of the most common were the gelugons. Stygia was the second favorite layer of the ice devils next to even colder Cania. They could polymorph into giant sharks to more efficiently fight in its putrid waters, although they put that off as long as possible, instead magically flying over the water since they were deft enough to avoid the lightning. Stygia was also one of the largest population centers for succubi in the Hells, rivaling Dis and Malbolge in that regard. Cornugons were also notable for dwelling in groups within every known steam trench, as well as occupying the volcanic rifts of the layer's mountains when not ordered elsewhere.
Other devils common in Stygia included the aforementioned erinyes, osyluths, storm devils, and spinagons. There was also a noteworthy presence of imps, barbed devils, and legion devils.
While not necessarily present, one also had to mention the existence of cambions dedicated to Levistus. These chained cambions were guardians and torturers completely restrained by their bindings, which crawled along the ground to let them maneuver and acted as a conduit to their tortured psyche, allowing them to shoot the minds of their victims into the frozen dark of Stygia through the metal's touch.
===Petitioners and Planars===
Mercenaries from across the planes played a key role in the war for control of Stygia, including the yugoloths. Of note among that race were the merrenoloths, whose person and passengers no devil below greater status would touch unless off the skiff, whether in Stygia or most other layers. Though osyluths might try their hand, the merrenoloths were the greatest boatmen of the River Styx; their mastery allowed them to effectively bring anyone they chose into Stygia, and they were not opposed to ferrying armies so long as it was not wrapped up in the Blood War.
On the note of river transport, the Styx was the means by which those picked up on the Shelves of Despond (the clammy rocks of Avernus where damned souls first appeared in Hell) were taken to Stygia. They were quickly taken there on barges, usually to the city of Tantlin or Levistus's Tomb. Getting them in was a tricky process as ships struggled to dock near the spars of ice jutting from beneath the waterline near the iceberg and the mournful dead were unloaded and tirelessly herded by ice devils.
Curiously, the souls of the damned seemed physically present in Stygia. Those who looked out over the ice could sometimes see tormented, screaming souls squirming in the ice like tomb stones, and Levistus's prompting could raise sobbing white faces out of the shifting blocks of ice. Other than them, there were other petitioners to deal with. The liches and mummies among the diverse inhabitants of Ankhwugaht occasionally left the realm to trade with Stygia's other inhabitants. The sahuagin of Sheyruushk meanwhile did little commerce, but did offer extra muscle and occasionally took people on squid hunts.
Aside from the dead, many of the trade cities along the Styx were populated by planars. A few tribes of frost giants were known to inhabit the layer.
===Others===
Despite the lack of true prey besides lemures, the Stygian swamp contained a thriving and robust ecology of frosty, fiendish and unexpected beasts on both the icy land and in the frigid sea. The Stygian wilderness was inhabited by creatures such as mammoths, as well as frost worms and remorhazes that competed for food with polar bears and dire wolves On the subject, Stygia had an interesting population of supernatural canines. Hell hounds were one of the creatures that might serve as food, and there was a population of winter wolves. All of the latter creatures ultimately answered to Geryon's duke Amon after he tamed the largest of them, Soulfang, putting himself at the top of their hierarchy.
The ecology beneath the pack ice was also interesting, although it had been heavily altered by the presence of Sekolah. Long ago had the great white shark god devoured all potential rivals, ridding the sea of sharks and killer whales, save in the cases where such creatures were hers (certainly sharks were still present but a presence of killer whales was unclear). Sekolah's servants, including sahuagin, sharks, megalodons, and truly colossal sharks unlike anything on the Material Plane, were immune to the Styx through their god's blessing, making hazards of themselves even there. The colossal sharks stood out as not even being animals, but extensions of Sekolah's power who consumed more out of curiosity and viciousness than a need for meat. Disregarding them, the Stygian sea was home to beasts big and small ranging from predatory giant octopuses and squids to prey including great whales and many smaller, blind fish.
However, despite Sekolah's efforts, a more alien presence existed in the lightless depths of the Stygian ocean, an obvious example being krakens. But perhaps a more dire threat was the presence of aboleths in the Stygian sea, creatures changed by the influence of the Nine Hells. Infused with the frozen, evil magic of Stygia they had become an entirely new species, and might one day become a new kind of devil entirely. Stygian aboleths ruled nations of aquatic baatezu and slaves culled from countless realms, such as fiendish skum, and were known to keep cities in the remote corners of the plane.
Most of the native denizens of Stygia were careful to stay near the ground unless they were immune to electricity altogether or such quick and agile fliers that they could swoop and dodge through the plane's blasts of lightning, such as some of its devils.
==History, Rumors and Legends==
Stygia was a peculiar plane with origins shrouded in mystery, one speculated to not always have been part of the Nine Hells. Rumor had it that it was originally a world on the Prime Material plane that was facing certain doom, whose inhabitants then pledged their souls and the world itself to Asmodeus in exchange for safety, resulting in the world being transported to the Nine Hells. This hypothesis was based on the unusual variety of creatures native to the Material Plane that inhabited the layer, although no more decisive evidence had ever been found to support it, at least by the archmage Tzunk. This theory did however bear a striking similarity to a verifiably true event where, in eons past, a large city of exceptionally large aboleths used their magic to transport an entire world full of minions from the Material Plane into Stygia, where the aberrations flourished.
Regardless of the overarching truth of the story, speculation that artifacts of the original world sat at the bottom of the Stygian Sea remained untested. The simple fact of Sekolah's presence beneath the water's surface was enough on its own to keep people at bay. Devils were not exempt from the predations of the shark god or their minions, with their sharks in particular relishing the chance to sink merchant craft and the boatmen of the Styx alike. No one wished to speculate in detail about what beings lived below the surface, but there were often rumors, as apocryphal as they might be by most estimates, of ancient betentacled gods trapped beneath the ice.
===Levistus and Geryon===
As far as could be ascertained, Stygia was originally ruled by the archdevil Levistus. Levistus was an ancient being, said by experts to be older than even Dispater (a claim Dispater's supporters contested), an entity who was himself so unimaginably old that it was difficult to recall his origins or classify him as a "type" of devil. He had proven himself able and cunning when the baatezu first conquered Baator, and it was his charm and competence that saw him installed as Stygia's Lord of the Nine.
For eons Levistus ruled Stygia, earning himself a reputation across the planes as a legendary swordsman who ended many conflicts in lethal duels. Geryon was also present at this time, and believed to have been an ally of Asmodeus from before the baatezu devils had come to be. Though a powerful archdevil, he ruled no plane of his own, and instead served as Asmodeus's personal agent, acting as his herald, spy, saboteur and advisor in the Hells. Otherwise he went when on pillaging expeditions when summoned to the Material Planes by foolish mortals, netting himself great wealth.
Yet Levistus, powerful as he was, was not content with his station. Indeed, the "rogue archdevil" as he was known, was a treacherous sort even back then and even by the standards of devilkind. He was among the first fiends to try and overthrow Asmodeus, having had ambitions beyond his realm and plots to achieve them just after being granted it.
===Levistus's Crime===
There was some conflict as to whether Levistus had been deposed before in the ancient past, perhaps even more than once. He and Geryon were sometimes described as having fought over Stygia even before he was frozen and sometimes not. In any case, Asmodeus was known to have demoted archdevils, but Levistus's infamous offense was considered sufficiently grievous that the fact he was merely imprisoned could be seen as a mercy. 
Soon after his latest triumph over Geryon, Levistus believed he found a path to Asmodeus's defeat, specifically through his household. The public story was that Levistus went before Asmodeus's consort Bensozia, who by this time had achieved sufficient esteem and trust from Asmodeus that she was sent to inspect other Hells along with the King of Hell's constable Martinet and several pit fiends. As she traveled through Stygia, Levistus offered to make her his queen in exchange for helping him overthrow her master or outright attempted to ravish her. For her refusal Levistus murdered her and all guards but Martinet, who escaped. 
This version of events was almost certainly propaganda, for Bensozia hated Asmodeus for her own reasons, the depth of her loathing being something not even Asmodeus predicted. The alternative, whispered version of events painted a much different picture. Rather than refusal, Bensozia accepted the archdevil rake's proposal, and allied with him for many years, traveling to Stygia whenever she could to whisper secrets and provide him every possible advantage. This was depicted as a loveless, exploitative partnership done only out of mutual desire to unseat Asmodeus. But Levistus's long-running weakness had always been his compulsive need to betray, even at his own cost, and their conspiracy was eventually unraveled by Asmodeus's disobedient daughter, Glasya.
On one of Levistus's visits to Asmodeus's court, the dashing rogue stole the heart of the Princess of Hell, and in her Levistus saw the opportunity to further turn Asmodeus's family against him. He maintained a second affair with Asmodeus's daughter, fully aware of the danger if any one of them knew the extent of his actions but unable to resist the temptation of such a treacherous tryst. That very thing happened when Glasya, having come to Stygia after another fight with her father, found her mother occupying the very arms she hoped to flee to. Glasya, who already hated her mother, was driven to murder her on her way back from Nessus.
When Martinet, charged with enforcing order in the Hells, discovered the assassination, he moved quickly, concluding that the disaster would make Asmodeus seem weak. He slew the other pit fiend witnesses and pinned the murder on Levistus. Thus was Levistus framed to cover up his true crime, breaking the household of Asmodeus through his simultaneous affair with his wife and daughter. Whether or not Asmodeus ever cared for Bensozia, allowing the one charged with her murder to go unpunished could not be abided. Levistus was stripped of his title, sealed in ice and had his domain passed to Geryon but a few years after getting it back. 
===Geryon's Reign===
Geryon's rule (at least as to be described) seemed to extend both before and after the murder of Bensozia. In ironic contrast to ambitious Levistus, Geryon initially resented his position of increased authority and pined for his relative freedom, but he slowly came to enjoy it, becoming more cruel and malicious as he came to appreciate tormenting his inferiors and playing infernal politics. Reports varied on how long he ruled, but accounts describe it (and Levistus's imprisonment) as lasting for centuries if not millenia.
During Geryon's dominion he ruled from Tantlin, which was best described as his castle, and seldom left. There he would delight in luring powerful creatures from beyond the Hells to Stygia with carefully crafted tales of magic, knowledge or treasure in hopes of making them the prey in one of his unsporting hunts. He delighted in physically battling lesser devils and captured intruders, sometimes chasing them for long periods throughout the halls of Tantlin. At times these hunts would lead out into the gravel-strewn quarries nearby, where spinagons, hamatula, hunt survivors and similar subjects forever mined stone blocks for the walls of Tantlin and other places in the Hells.
During this time, Geryon was perhaps the most content out of all the archdevils, and the least interested in the endless political struggle of his kind (at least as a vehicle for the incessant pursuit of power, he never missed a chance to act against his hateful neighbors). During his long tenure he was relatively weak among the archdevils, and did not distinguish himself from his peers much, but neither was he seriously threatened or troubled. His vassals were outwardly loyal and often called upon to aid his interests.
Geryon's chief lieutenant Amon (who would explore every inch of Stygia and tame its winter wolves at this point) commanded forty companies of bone devils and butted heads with Agares, who commanded thirty-one of the same. Machalas, who commanded eleven companies of barbed devils, simply encouraged the feuding between the other generals to position himself as more reliable, while a pit fiend named Fecor commanded eight companies of cornugons. Geryon also retained the service of the "Prince of Beasts" Alloces for several years, the monster-making fiend keeping his menagerie of bestial horrors, acting as a combination kennel-master, huntmaster, head breeder and creature creator.
Geryon's sovereign interests meanwhile were safeguarded by his magistrate Herodias and his bailiff Gorson under the watchful eye of his consort Cozbi, who despite her quiet ways was attentive and not easily tricked. Herodias maintained the realms security, assuming command over the defenses during Geryon's hunts while otherwise training and ordering Geryon's bone devil legions, while Gorson observed the daily goings on and internal politics of the Hells as a whole while ordering and coordinating the amnizu in Geryon's absence. Thus they held much of the actual power in Stygia while acting in Geryon's name, allowing Geryon to continue his hunts while retaining his influence (if not increasing it).
Notably during this period, amnizu did not occupy the preeminent position in Stygia they later would. They dwelled in the swamp, constantly tormenting lemures as they splashed and wailed in the muck unless they were summoned for a mission. But sometimes bone devils or horned devils would enter the swamp, and if not to join in the fun, would start chasing a few of the styx devils, forcing all others present to band together to drive the interlopers out.
Other noteworthy events during this period included a ploy by Baalzebul, then ruler of both Maladomini and Malbolge, to manipulate mortals into removing a gem known as the Devilbane from Stygia. This prompted forces from Geryon and Asmodeus himself to try and seize the gem from the warded holy tower in which it was kept, as well as a counterattack by celestial forces under Tyr and Osiris. It was during this event that Set was in the process of building a pyramid in Stygia. Not content with his dominion in Avernus, his mad, yet ultimately successful plan was to use the structure as a focal point of power to gain a "beachhead" in the Frozen Wastes, which would ultimately become his new primary plane in the Great Wheel. Sekolah meanwhile was already present, and known to converse and often devour Geryon's ambassadors, even if Geryon himself wasn't afraid of the seabound god.
===The Reckoning===
The stability of Geryon's reign would begin to falter at a certain point. His influence began to fade and Alloces abandoned him in favor of a mercenary approach to his services. But Geryon still had a role to play, that of Asmodeus's agent during the Reckoning of Hell. Though the Stygian archduke feigned allegiance to the faction of the Cold Lord Mephistopheles, he secretly supported Asmodeus against the machinations of his rivals. Indeed, Geryon encouraged the treachery; during the affair he was secretly having relations with the night hag Malagard, the consort of his rival ruler in the sixth layer Moloch, and had her convince him to join on the promise that he could rise up through the chaos to rule the Hells.
Geryon fed Asmodeus information on the conspirators’ activities up until the final encounter. It was his great horn, the symbol of his authority during his regime, that signalled the pit fiend commanders to turn on their archdevils. Surrounded by Asmodeus's armies and their own turned against them, the archdevils were left in humiliated disarray. Moloch, however, did not retreat, bolstered by the poisonous words of Malagard offered to him at Geryon's request. For his defiance he was one of the only lords to be officially and truly removed from power at the end of the Reckoning.
But to the surprise of everyone, the other lord in that category was Geryon himself, the only duke to remain loyal. Stunned, Geryon was stripped of his rulership and a substantial portion of his strength before being banished. Then, to the dismay of everyone, Geryon's replacement was none other than treacherous Levistus himself.
===The Frozen Prince===
Levistus had wasted away in his icy tomb for millenia if not eons, conscious but unable to act. He spent centuries watching Geryon's rule, contemplating what he would do if given authority again, hatching a grand scheme born of unimaginable patience. When Asmodeus did inexplicably reinstate the Prince of Betrayal, Levistus was neither particularly grateful nor outwardly surprised, and seemed prepared to reclaim his title and authority immediately, albeit with certainty that some sort of trap awaited him. In a sense he was correct; he was still being punished, and though awakened was not freed. Instead, he was left to languish in immobility, and was also now mandated as part of the penalty to offer escape and safety to desperate individuals.
Levistus's operatives attacked and slew most of Geryon’s generals, lest they plot against the newcomers. As a result, most of Geryon's loyal followers died in the battle leading to Geryon's fall from rulership and the subsequent fights during their period as outcasts. This fighting was furthered by the infamous pit fiend that took over Tantlin after Geryon's fall, who encouraged it to happen within city walls. Of the loyalists, the only one who survived intact was Amon, who was outraged that Geryon was punished when he should have been rewarded and stayed behind in the Hells to exact vengeance in his name. With Agares and Malphas remaining and tentatively at his command, Levistus began his long-awaited revenge.
Rivals who believed Levistus's condition would limit him usually suffered for their miscalculation. Belial for example, who imagined he and his daughter would be able to conquer the two Hells below his rather quickly and was disappointed that a dangerous foe like Levistus was put in charge, sent an army into Stygia that found itself decimated, after which he focused on outmaneuvering Levistus politically. Set, who had firmly established his presence in Stygia at this point, had also entered a shadow war against Levistus, each working against the others in subtle ways, with Set for his part using his divine minions to wreak havoc on Stygia's cities.
In reality, the Frozen Prince's subtle schemes played out slowly but inexorably, both despite and because of his condition. With nothing to distract him in his tomb, he could focus his full attention on answering entreaties from other worlds, commanding ceaseless intrigues against his peers, and controlling a network of espionage and diplomacy impossible for most minds to manage. His schemes were planned to the smallest details, both in Stygia and without. During this period, Levistus was usually too busy scheming and governing Stygia to bother manifesting an aspect. 
Some of the Material Plane believed Levistus was not interested in politics, but most planar beings knew otherwise. Levistus was constantly plotting to steal power from his rivals and had every intent to conquer an adjacent layer of Hell (probably the sixth) in the likely mistaken belief that such power would allow him to break free. He garnered a reputation for being particularly greedy in this regard compared to his peers, such that word spread in Stygia of a coming assault for which his amnizus were recruiting mercenaries. Such blatant maneuvers at their collective expense alienated Levistus from any lords who would still deal with one so outside Asmodeus's favor.
But Levistus's true plan of this era extended beyond simple power grabs and territory skirmishes, being so grand in scope that his peers would likely question if it was possible. Not long after first being frozen, Levistus began stockpiling souls in his prison, and he and his remaining loyalists rationed their soul consumption to the point of starvation. This rationing was extended to all Stygia upon his return to power, turning the fifth layer into a place of desperately ravenous devils. Souls were traded for acts of treachery or for even more souls in exchange for one specifically desired by another devil, netting even more for his ever-swelling vault. All this was merely the preparation for his plot's climax. 
Levistus's true plan was to turn Stygia into the second wall in a barrier enclosing the middle Hells. Prior to imprisonment he already had dealings with figures beyond Asmodeus's direct control, such as exiled archdevils and forsaken former creatures of the Hells. These would lead splinter cells of pirates and saboteurs in his greater network. When everything was ready, the Rogue Archdevil's motley crew of infernal outcasts would cut off the flow of souls into the Hells from its starting point: Avernus. Combined with some bribes to powerful figures like Moloch and the Dark Eight, the siege would allow Levistus to slowly advance on the upper layers, sieging his enemies into submission, for only his devils were accustomed to soul starvation. Those below could suffer until he was ready for them, the poetic irony of the plot being that his rivals, even Asmodeus, would fall knowing the feeling of being trapped in one's own domain.
===Return of Geryon===
Geryon's fate after his loss of position was unclear. There were reports of banishment, destruction and some sort of final battle for control before he faded into ambiguity in Stygia. However, one of his last known appearances before his proper re-emergence made clear the sheer diabolical depths of Asmodeus's machinations.
It was speculated that Asmodeus was concerned with Levistus's designs on another layer, and so called the brooding Geryon to his fortress of Malsheem with an offer to support his reinstatement, provided that he serve in his plan. He had foreseen the threat Levistus would inevitably pose centuries ago and allowed it to play out up until the Rogue Archdevil no longer served his purposes, all while simultaneously establishing the mechanism to unseat him through Geryon. All Geryon had to do to fully win his support was conquer the Temple of Neohed, which would teleport below the ice of Stygia as part of Asmodeus's own plans for a global corruption event.
Aware ahead of time where Neohed would arrive, Geryon designed and built Coldsteel, completing construction and gathering his forces there in secret. Despite Geryon's efforts Levistus was aware of Coldsteel and had his amnizu watch it to learn more, even offering encouragement to adventurers seeking to go down there for their own purposes. In the ensuing chaos, Geryon's consort Cozbi, up until now kept alive with magic and machinery long after she should have died, finally perished too. The invasion ultimately appeared to have been stopped, for Geryon's power was not restored, and the deposed duke was left to languish once again as Asmodeus was denied his prize.
===Levistus's Temptation===
Despite Geryon's lack of success, Levistus had his own troubles to worry about. Though he had kept her occupied beforehand, the nameless pit fiend of Tantlin had descended into anarchy that only grew worse as time went on, with gang fights being amazingly common and the city effectively run by criminals. So encompassing was the chaos that Levistus's rivals began questioning his lawful credentials. Before the complaints reached a crescendo he was forced to act; he reinstated his authority, rewarding survivors with positions and promotions, while having his amnizu factorums freeze the former ruler solid and shatter her into shards, which would become highly coveted collectibles in Stygia.
Levistus was further challenged by the rise of Glasya after the death of Malagard, who had risen to rule Malbolge after Moloch ( and whose ritual to godhood Geryon was rumored to have a hand in ruining). Like Geryon's removal, her appointment was a mystery to the historians of Hell, but with the ascendance of Asmodeus's daughter, a theory arose to explain all of these strange maneuvers.
By raising Levistus up to rule Stygia without releasing him from his prison, the energy taken from Geryon that would have gone to his replacement could be preserved to promote Glasya, with the Hag Countess acting as a mere placeholder until his daughter was ready to take the throne. Under this theory, Levistus's blatant acts of antagonism was simply a smokescreen to distract from Asmodeus's plan for his child. If this theory was true, it would only further accentuate the multilayered complexity behind Asmodeus's schemes. Levistus himself had come to accept the theory despite loathing its implications, namely that all his own plots were simply cogs in Asmodeus's greater machine.
Furthermore, Glasya's rise posed a more direct threat to Levistus. Whatever his history with Glasya and her mother, she expressed utter hatred towards him and intent to murder him. Generally this was considered an empty threat given his current invulnerability, and she lacked the power to mount a full-scale invasion of Stygia. However, she notably had a strange alliance with the nominal ruler of Phlegethos at the time, Fierna. Unlike her father Belial, Fierna had no interest in frozen Stygia, which was made all the stranger by the fact that the pyromantic archduchess was also immune to cold, which led some to speculate she was seeking mastery of the element to take over Stygia or Cania. It was not unlikely that Glasya intended to use Fierna to shore up her forces when she finally attacked Stygia, a scheme to be considered given that the archduchesses were "friends" and Fierna had her cold immunity even before Glasya's rule of Malbolge. 
In the wake of these changes, Levistus's core instinct to betray rose anew, and his patience ebbed. Though he knew he should behave himself, it was at this time he nevertheless accelerated his plans to upend Hell's power structure. Once again he intended to go after Asmodeus, specifically by subverting his court, and even by trying to seduce Asmodeus's rebellious daughter once more.
Around the time the Blood War was restarting during the Second Sundering, the battles that took place in Stygia left parts of the Frozen Wastes utterly destroyed, and rumor had it that the demonic invaders managed to break into Levistus's storeroom and steal powerful artifacts.
===The War Goes On===
When Geryon finally disappeared from infernal history, he had lost all hope for the future and began to question the point of his own existence. It was that Asmodeus, who hungered for the souls of those with shattered faith, feasted well upon his, after which he was little more than a vestige. Geryon aimlessly wandered the Astral plane wracked with despair, believed by many to have died or returned to the astral energies of the wider planes. In truth he found himself called to Tytherion, the Endless Night, where he was but one devil amon a wasteland of many kinds of exiles. Alone he brooded in his cave before he came to the conclusion that Asmodeus would not cast him out without cause, and that he must desire him to do something that even the King of Hell could not be directly implicated in.
Whatever the ultimate cause or result of his deliberation, Geryon would eventually return to Stygia once more, intent to reclaim his lost status and still bitter about Asmodeus's rejection. He retook Citadel Coldsteel, close as it was to the plane's center like the city of Tantlin, and from there schemed to take Stygia back from Levistus. Unable to directly affect each other, the two archdevils turned Stygia into an outright warzone, with both sides seeking the knowledge to cement the position of their leader once and for all. Even this battle of Stygia, however, was thought by sages to be yet another ploy by Asmodeus, a test staged in hopes of purging the worst impulses of his minions, and if not, to clear the way for a new competent to rise up and rule Stygia in their stead.
==Appendix==
===Appearances===
===References===
===Connections===
Category:Locations on the River Styx
Category:Bodies of water
Category:Locations in the Lower Planes
Category:Locations in the Outer Planes
Category:Locations in the Great Wheel planes
Category:Locations