This is an exercize in creative writing I undertook a few years ago as part of a project on a D&D community I frequent: a profile of an Arch-devil, sans game stats. It never made it into the final project, but it was still a fun experience and I enjoyed writing it.
I only wish I could harness this kind of creative power to write fiction.
Why yes, I am stroking my own ego by posting this, why do you ask?
Note that originally her name was "Zariel" and her successor was "Bel", but I had to change them to "Astarte" and "Bael" because that's what the mods wanted. I didn't like that because the actual Astarte and Bael were benign deities who had nothing to do with Hell. As a compromise, I tried to distinguish between the infernal versions of Astarte and Bael and the original deific versions by using alternate names for the latter (Ashera and Baal) and explaining the reason for the similarities in the names within the text.
The Archdevil of Destruction, Deposed Lord of the First
aka Zariel, Zavebe
Shortly after the Great Fall, the Seven Virtues of Heaven saw the need to keep a watch on the fallen angels that descended into the Hells. The Supreme Virtue of the Seven Heavens chose one of its most powerful servants, a solar named Astarte, as the chief watcher over the fallen celestials in Avernus. Astarte was originally a vassal of the Virtue of the Sixth Heaven, and the general of one of the greatest flights of celestials in the Upper Planes; unlike her fellow solar Triel - now the devil Beelzebub - Astarte had never shown any signs of corruption, and seemed a perfect choice for the job of warden. So it was that, with an army of angels, Astarte flew through the planes of Arcadia, Mechanus, and Acheron to the blasted plains of Avernus in Hell.
Fighting off the hordes of devils that inevitably resisted their arrival, the forces of Astarte built a celestial fortress of bronze on Avernus, her stronghold against the evil of Hell. Their task was to keep a watch on the doings of fallen celestials in Avernus: to make sure that they made no attempt to return back to Heaven to exact vengeance. They repulsed several such attempts on the fallen angels' part, and the Bastions were confident in the outcome of their decision.
Unfortunately, they underestimated the corrupting nature of Hell's very fabric. The methods Astarte employed grew colder and harsher with each passing century, and the celestial fire that burned in her heart dimmed. Before a millenium had passed, Astarte and her similarly dispassioned followers began working with Hell's devils, who also sought to control the fallen celestials. Astarte stopped communicating with the Lords of Heaven and focused entirely on keeping the fallen in check. She allied with Urukbaramael, a solar who had fallen with Eblis and Triel, who employed similarly violent methods with his fellow fallen in his vain attempt to fall back into the Virtues' favor; together the two, both filled with misguided single-minded righteous fervor, struck fear into many of the fallen, and Astarte sank deeper into cold heartlesness.
In time, Astarte and Urukbaramael laid plans to sack the infernal lair of the terrible Chromatic Dragon, Tiamat, the Lord of the First at the time. Normally such a campaign would have failed, but the fallen hosts of the two caught the Lord of the First unawares. Together, Astarte and Urukbaramael stormed the Caverns of Greed; fighting her way past Tiamat's five draconic consorts and to the Great Hoard of the Dragon Queen, Astarte laid waste to Tiamat's guard, withstood her foul spells and the attacks of her vile breath, and brought her sword to bear while Urukbaramael kept a pair of Tiamat's Dukes at bay. She lifted her sword into the air and prepared to plunge the enchanted blade into the Lord of the First's blackened heart - until a terrible row split the air, fire engulfed the hoard-room, and the face of Asmodeus himself appeared before Astarte.
While Urukbaramael, the Dukes of Avernus, and even the Chromatic Dragon herself cowered at the horrible sight, Asmodeus told Astarte that if she would let Tiamat live, he would anoint her as the new Lord of the First Hell. Astarte considered the proposition for a moment - and accepted. As the diabolic power of the King of Hell transformed her, she left behind any pretense of loyalty to the Supreme Virtue and Heaven; as she took her place in the Great Machine of Hell, the last scraps of goodness left in her disappated. She was now a devil.
Asmodeus left Tiamat and her brood to guard the passage into Hell from her dragonspawn pits, and Astarte, with Urukbaramael at her side as her consort and right hand, began to establish herself as the new Warlord of Avernus, ruling from her Bronze Citadel. Part of her agreement with Asmodeus was that she continue to keep the fallen angels under check, a task she found much easier now that she had Tiamat's legions of devils as well as her own host of "loyal" fallen angels at her beck and call. Urukbaramael gladly led her armies, torturing and destroying his fellow fallen. So terrible was the dark army of Astarte that the fallen dubbed her the Lady of Destruction, a title that stuck with her among the rest of the diabolic hierarchy.
The other Archdevils - especially the former celestials Belial, Moloch, and Beelzebub, who resented her for her original purpose in Hell - were quick to label Astarte an upstart, but she cared not. She had no allies among the fiends besides Urukbaramael. The only other entity in Hell with whom she had nonagressive contact was the goblin deity Bargrivyek, whose dogma of strength and unity against the dissident she respected. It was not uncommon for Zariel to send a small detatchment of devils and fallen angels from time to time to aid Bargrivyek's goblins and hobgoblins in their raids against Draukari, the realm of his rival deity, Kurtulmak of the kobolds. In those times goblinoid ambassadors were frequently stationed in the Bronze Citadel, and fiendish emmisaries made their residence in Bargrivyek's spectacularly misnamed realm, the Peaceable Lands.
Outside of Hell, Astarte had contact, aggressive or otherwise, with even fewer entities. Only one being cared about her appearance in Hell: the fertility-goddess Ashera of the Canaanite pantheon. Using the similarities between their names as a stepping-board, the cold-hearted Astarte took the opportunity to establish a few cults by subverting Ashera's worshipers; but since Astarte was under the protection of the Overlord of Hell, Ashera could do nothing about it. (Interestingly, in a repetition of history, Astarte's successor Bael would take advantage of a similar situation by usurping worshipers of Ashera's consort, the great thunder-god Baal; both devils contributed to the tragic villainization of the Canaanite pantheon.)
By no means did her lack of political ties did not stop Astarte from scheming against her fellow Lords of the Nine. She placed numerous spies in the courts of Dispater and Mammon, and had designs of conquering Dis (a notion which the other Lords found laughable). She reserved special hatred for Great Belial and the Lord of the Flies for reasons she no longer cared about, and laid countless plans to undo the two fallen angels. She paid little attention to the Blood War, focusing her attention on routing the fallen on Avernus; she left the front against the demons of the Abyss to her pit fiend general, the devil known as Bael.
When the civil war later to be known as the Dies Irae swept across the Hells, Astarte allied with Beelzebub, Belial, Moloch, and Mammon mostly to keep an eye on the four; she could not have forseen the outcome of that decision. When it seemed that the infernal hosts of Beelzebub and Mephistopheles would actually defeat Asmodeus, Astarte left the Bronze Citadel and made haste to Nessus with the other five Lords to witness the spectacle - and then Geryon sounded the signal and the armies of the Lords all turned against their masters. So the Reckoning of the Dies Irae came to pass.
For reasons still poorly understood, the King of Hell reinstated all of the Lords save Geryon (his only loyal vassal among the Nine) and Moloch (who foolishly challenged Asmodeus for lordship again shortly after), who were replaced by Leviathan and Lilith respectively. Astarte returned to her Bronze Citadel humiliated, with nothing but her newly kindled hatred for Asmodeus occupying her mind. If the Reckoning taught the devil Geryon the worthlesness of blind trust in Hell, it taught Astarte not to ignore the sovreignity of the Dark Lord.
After the Reckoning, the Lady of Destruction lived up to her name more than ever, wantonly laying waste to fallen angels, invading demons and yugoloths, and rogue devils alike. Her consort Urukbaramael was disturbed by what he saw. He, at least, had hopes of returning to Heaven; it was his monstrously cruel methods that kept him in Hell. He recognized that Astarte now had no purpose whatsoever, and resentment grew in his heart for his mistress. When at last her general Bael swept into the Bronze Citadel, his aim to usurp the Lordship of Avernus, Urukbaramael willingly let him into Astarte's throne room, looked on apathetically while his one-time mistress was routed, and then left to pursue his own twisted agendas in Avernus once again.
In the battle that ensued, Bael fought his way past Astarte's defenses in much the same way Astarte had fought past Tiamat's. Bael's ferocious onslaught surprised her: although she was perhaps the dullest of the Lords of the Nine, it quickly occured to Astarte that the King of Hell was setting his will against her. She fought Bael like a titan enraged, but in the end it was futile, and the pit fiend subdued her.
In a coup well-known throughout the planes, Bael imprisoned Astarte in a chamber beneath her throne - now his throne - and began siphoning off her power. Her Lordship stripped from her and given to Bael, Astarte could not hope to escape from the Warlord's snares. Still she fights Bael's magic with hers, but to no avail: unless Asmodeus himself sees fit to release her, there is no hope left for the fallen angel Astarte.
As already noted, a few scattered cults once existed that devoted themselves to Astarte, focusing on prolonging unjust wars and destruction, but upon his ascension, Bael saw to it that they were destroyed, generally by sending his devils to quash his prisoner's supporters.
In her prime in Heaven, Astarte was a beautiful yet powerful creature fourteen feet in height, with shining golden skin and flowing black hair; golden light shone from her eyes. Her beautiful appearance did not change with her ascension to Lordship - except for the loss of her wings, which simply disappeared. Over her years in Hell, however, her countenance grew weary and haggard, her hair turned gray, and the light in her eyes died. Now, held immobile in a chamber within Bael's fortress, she presents a stark figure in tarnished silver armor with dead gray eyes that stares down upon would-be visitors. She can still speak and use most of her spell-like abilities, but otherwise she cannot move (and so cannot cast spells with somatic or material components, etc.).