Fierna

In name, Lady Fierna ruled Phlegethos, commanding the fiery layer from her palace of rock and magma. In truth, her father, Belial, was the power behind the throne.

Description
Fierna appeared to be an incredibly attractive young woman, a lithe, statuesque, seductress of stunning physique. Tall, dark and sensual, her garments were as royally fine as they was scantily clingy, furthering her image as a being of perversion and indecency.

Giving away her infernal heritage were the small pair of horns that emerged under her hairline, and even then the fiendish features somehow managed to enhance her enchanting appearance. Her red eyes shined and smoldered like fires were dancing within them and implicit promises of pleasure could be gleaned from her gaze.

Personality
Befitting an archdevil of fire, Fierna was well-known for her short-fuse and volatile personality, her temperamental temper striking fear in almost any devil. Her rage escalated quickly, frustration leading to fury, which erupted, quite literally since she angrily moved about on fire when enraged, into bloodthirsty vengeance, often times with little warning. Disregarding her anger-management, she was self-absorbed, sadistic and just generally mercurial, flitting about like a lit flame between her various obsessions and displaying a "party girl" attitude.

"Fly my pretties, fly! Fly!"

- Fierna commanding her spinagon legions

However, assuming Fierna was just a bratty beauty was a grave mistake, for both political schemers and would-be courtiers. Fierna was prodigiously brilliant in the art of emotional manipulation with charisma to match that of Asmodeus himself, lighting fires in the hearts of mortals and immortals alike that she could control like any other. Her explosive outbursts seemed chaotic and random, but she was a being of law and the opposite was likely true, with her simply following a pattern that perhaps only she understood.

Though she saw being viewed as incompetent a useful ploy, she was no less adept at politics than other archdevils, but had no interest in taking part in the overcomplicated, governmental web. The black-hearted archdevil had more hedonistic goals, desiring to use her position to indulge in luxurious comforts and lecherous pleasures while allowing others to actually administrate. At least, this was her stance at one point, but later on she became more professionally-minded, still toying with lesser beings, but making efforts not to immediately discard them upon growing bored and attempting to enter the "grownup" world of diabolical conspiracies and power plays.

Powers
Fierna had unmitigated mastery over fire, able to create it and cast a vast array of fire-based spells as well as control all fire within Phlegethos. Rather than rely on weapons, she fought with a blade of pure fire that she summoned to her hand, twice as powerful as ordinary flame blades. She rained burning death upon her enemies, first conjuring a fire shield before destroying her foes with a meteor swarm and flurries of fireballs.

Though she eagerly partook in slaughter, particularly enjoying the feeling of hot blood splashing against her, she only entered melee if victory was certain and was smart enough to know when to retreat, often with teleportation. Instead, she engulfed her foes with flames from afar, quickly summoning reinforcements in the forms of spinagons, barbazus, hamatulas or a cornugon.

Strangely, magical or otherwise, the cold did little to stymie Fierna's flames and similarly water could not extinguish them, ironically only earning her fiery ire and getting the presumptuous assailant scorched.

Realm
Fierna ruled the fiery layer of Phlegethos, the most archetypal of the Hells that commonly appeared in mortal minds when Baator was mentioned. Like the Plane of Fire, the unending flames and unbearable heat swiftly scorched most forms of life, with much of the scalding expanse being covered in ashen hills and smoking plains. Of the lawful planes of Hell, Phlegethos was the most environmentally chaotic; tremors were common and violent eruptions or the random openings of fissures were sporadic, although despite making it more dangerous it gave trespassers a wider choice of hiding spots.

The tortured hellscape was rife with mountainous volcanoes which spewed the rivers of molten magma that dominated the plane,  the structures of Phlegethos having to be made to withstand its random redirects. All bodies of the liquid lava were interconnected, either in bubbling pools, lakes of fire, or igneous seas. The firefalls, where the fiery streams fell from sharp ridges, made it one of the most visited hells, at least by magic-wielding outsiders that sought to use the flames in works of incredibly alchemy or magical item forging.

Supposedly, Asmodeus killed the original divine master of Phlegethos, his grave being a foundation for some crucial part of the plane. Regardless of how it was then, Phlegethos was currently a place of pain, with fires that seemed to harbor a strange, merciless sentience. Though welcome denizens, even those not immune to fire, seemed unharmed by them, intruders found that the flames leapt through the air, unnaturally bending to gleefully ignite them and their possessions. Even without the jumping flames illuminating the starless void above, simply staying still in Phlegethos was likely to get one destroyed, if not by the pyroclastic pumice interspersed throughout the flesh-roasting air then by one of the roaming inhabitants.

It was the most traveled of the Nine Hells, with hamatula guard patrols constantly hunting for intruders. Other common inhabitants, many of which stayed in the stinking fens on the outlands of the layer, included lemures, spinagons, imps, barbazus, abishai and cornugons. There were also the less devilish efreeti and hell hounds as well as lawful evil fire elementals and mephits, the latter of which worked as spies for any who would reward them.

Abriymoch
The seat of Fierna and Belial's power was the stronghold known as Abriymoch, the primary, if not only, city in Phlegethos. It was built in the caldera of the largest volcano in the realm, a hollowed out mount still overrun with molten rock. The buildings inside were constructed of jagged obsidian, igneous rock, dark glass, basalt and other crystals and the lips of the crater were crowned with towers. The fortress was composed of a series of chambers stacked on top of one another that opened into the volcano's hole through balcony-like structures and were connected to each other by stairs, shafts and a grand central spiral that snaked around the inner edges. Some rooms stretched throughout the inside of the volcano's sloping structure and had windows and other exits that opened to its outer walls, which were constantly poured over by lava rivers.

The city's actual streets were so flooded with lava that foot travel was impossible, forcing visitors to pay for one of the dented, green-steel gondola manned by hundreds of spinagons and barbazus to ferry them to their destinations. Green-steel, in fact, was a primary export of Abriymoch, the valuable ore being derived from Phlegethos's magma which made it a primary weapons and armor trade center in Hell. Relatedly, Abriymoch was the strongest citadel in the middle hells, with black towers that kept innumerable merregons and elite osyluths and malebranches. Hell hounds were also famous stays of Abriymoch, kept in kennels and raised in breeding pits that produced monsters to rival those defending Nessus.

Technically, the city was ruled by the pit fiend Gazra, although he answered directly to the archdevils, from a crystalline castle housing a legion of 5,000 hamatula reserves. His forces, also comprised of bone devils, were responsible for hunting down deserters, capturing unauthorized souls that slipped past the upper layers, spotting corruption amongst officers and checking the paper work for mortals and devils alike. Many unwary souls were killed by the zealous guardsmen as well as the hellish environment conditions, so few came to Phlegethos by accident, although intruders weren't much better off, being imprisoned in the seemingly inescapable dungeons under Abriymoch.

Abriymoch was also home to the Diabolical Courts, a maddening complex of loopholes and ancient precedents where various legal disputes between devils could be settled and souls condemned by an infernal contract could petition for their freedom. Ironically, despite being a place of unflinching law, matters of security and legalistic argumentation, Abriymoch was also a respite for many devils. Many of the laws governing Abriymoch allowed it to be run as a kind of carnal carnival, filled with infernal versions of taverns, theaters, casinos and various other establishments for the fulfillment of darker desires.

Fierna's Palace
"A paladin? How exquisite! Sit, please. Rest. Tell me about the god that would send such a bright soul on so long and dark a journey."

- Fierna chatting with a holy warrior.

A key example of Phlegethos's pleasurable aspects was Fierna's palace, a slender, serpentine tower of crystal outside of the city, wreathed in blue flame and surrounded by a ring of magma pools. Only she and her closest companions were allowed inside since Belial spent a majority of his time there. Exorbitant marble halls and a bejeweled decor could be found deep within the tower, and following a scorching staircase underground, were deep caverns known as Fierna's pleasure domes, each dedicated to a different vice. The floor had grates that allowed access to the prison cells below, many of which housed celestials and paladins for a bored Fierna to prod with a long lance at her leisure. A fair fraction of the captives were Fierna's ex-lovers, allowing her current suitors to see the fate of those before them which they rarely considered they could one day share.

Cult
Being a newer archdevil in the Nine Hells, the cults that arose to venerate her struggled to settle on a specific agenda or method of operating. Their temples were often improvised whatever they could find.

Relationships
Fierna is best friends with her fellow archdevil Glasya and would often spend time at her fortress in Malbolge. In imitation of her friend, Fierna eventually started to refer to herself as an "archduchess." She was also encouraged by Glasya to start building a network of devils and cultists separate from that of her father's forces, much to his chagrin.

Out of the several dukes that serve the domain of Phlegethos, Bathym and Zapan have pledged their loyalty to Fierna over her father.

Fierna once tried to court a mighty archfey, hoping to seduce them into relinquishing their soul. Her efforts ultimately went nowhere, but a group of the lord's satyrs became infatuated with her. Desiring some form of gain from her time spent on the lord, Fierna decided to corrupt the satyr with her infernal powers and transformed them into the creatures known as forlarren.