Asmodeus
Among the Infernal Legion, demons do not dream, nor sleep. For sleep is for the weak and foolish, those who allow themselves to become easy prey for the stronger and more cunning. The only demon of note to have dared to sleep every night was the former Prince of Darkness himself, whose overwhelming spiritual power and unparalleled combat skills allowed himself to be convinced that no one could succeed in harming him, even if they attacked during such periods of relative vulnerability. And that had proven to be his undoing.
But one can still contemplate, and reminisce. Asmodeus, the current reigning Prince of Darkness, closes his eyes, and thinks back to an earlier time, when he was foolish enough to challenge the Father of Demonkind to a fair duel for the first, and last, time. Though it was millennia ago, the memory remains fresh, and continues to strike a chilling chord in the Crimson Fiend's heart.
"For this once, I will grant you the privilege of making your first move," said Satan, the barest hint of a mocking sneer on his handsome face. His eyes, orbs of the deepest purple, swept over the red-skinned demon prince with a cold glint of amusement and pity. "Do not waste it, and do not disappoint me." As he spoke, three pairs of dark bat-like wings expanded forth out of the back of his elaborate pitch-black robes, their form and arrangement a twisted mockery of the white seraphic wings that the Adversary possessed prior to his fall from Heaven. Waves of demonic energy rippled around him, sending his dark hair and opulent garbs aflutter, and even in this leashed state his immense power was palpable to everyone present.
With a snarl, Asmodeus summoned his soulshard, the demonic trident that was the source of inspiration for humans' imagery of the devil's pitchfork. The head of the three-pronged spear burned with hellish crimson flames and noxious black smoke as its owner gathered power, preparing to unleash his strongest attack.
For an instant, Asmodeus met Satan's eyes, and saw the barest hint of a mocking sneer. It sent the then-young demon prince over the edge.
"TURN TO CINDERS!" Asmodeus bellowed, at the same time plunging the tip of his trident into the ground. A fiery demonic power rapidly spread from that point, turning the obsidian floor into lava imbued with poisonous fumes and Dark magic. Within mere seconds, the entire arena was transformed into the Lake of Fire, the Crimson Fiend's most dreaded spell that had claimed countless souls in Hell's name. But Asmodeus was not content with this display. Satan asked him to attack first, so he did, sending a further pulse of magic into the massive pool of Hell-magma. An instant later, a dozen or so geysers of liquid Hellfire erupted from all around Satan, converging upon his comparatively tiny figure from all angles simultaneously, while the entire Lake surged upwards in an infernal tide to engulf the Prince of Darkness whole. The moment Satan was swallowed, Asmodeus willed the magma to compress itself around its victim, producing temperatures hotter than the cores of stars all the while crushing Satan with immense pressure and entombing him in a volcanic prison. As the magma settled into a giant lump of obsidian, Asmodeus could already feel a small hint of fatigue in his bones, for he had just unleashed as much energy upon his enemy as he possibly could within such a period of time.
"Is this all?" Asmodeus suddenly heard Satan's voice resound throughout space around him, even though the Adversary should still be trapped inside his magma prison. "Pathetic."
The prison shattered.
The first things Asmodeus saw were six weapons, each cutting and piercing through the Crimson Fiend's hyper-dense demonic stone as if it was nothing more than wet clay. An axe, a scythe, a spiked mace, an undulating whip, a drill-like lance, and a serrated sword, each a soulshard in its own right that channelled Satan's terrifying power. As the stone prison shattered, Satan's own monstrous battle form was seen, a hulking six-armed humanoid dragon clad in not scales but heavy plates of the deepest, darkest fell metal that seemed to suck in what little light that existed in this arena. From the gaps in the creature's armor bled out a thick ooze of smouldering, throbbing Hellish red, spontaneously forming eerie sigils on the armor's surface, as if it was perpetually stained by the freshly spilled blood of thousands. Satan's shadow, now given material form by his power, trailed behind and around him as six serpentine heads of pure darkness, roughly following his limbs' movements. The sheer pressure from the Beast's aura felt almost solid, as if the fabric of space itself was held down by the shackles of Satan's immeasurable sin. His eyes, now akin to torches of blazing crimson power, pierced into Asmodeus's, and for an instant the younger demon felt a hint of fear.
Then the attacks began.
Asmodeus barely registered the creature's draconic jaws opening before his vision was engulfed by an endless expanse of blackness, its sheer power assaulting his senses and feeling almost akin to being swallowed by the ineffable Abyss itself. Armor of demonic stone reflexively formed around Asmodeus to protect him, but even through it he felt intense, searing agony as the blast scoured his body and mind alike. With his immense willpower, Asmodeus managed to not falter, before his senses screamed at him for an even greater power rapidly approaching. Through reflexes honed by the past decades of relentless training in the pits of Hell, Asmodeus barely managed to swerve to the right and back, before the black lance slammed itself into the ground where he stood an instant ago. Instead of pushing outwards with the shockwave of its impact, the drill-like weapon was spinning madly and suctioning in all things around it like a dark vortex, and it was all Asmodeus could do to steel himself and not be pulled in before the spear's gyrations ceased. He was only granted a second of reprieve, before the six additional shadowy heads of the Beast unleashed their own breath weapons, and this time Asmodeus focused power to create an exceptionally thick and well-fortified obsidian shield in front of him so he could-
Pain.
It took Asmodeus almost an entire second to realize that Satan was now standing to his front left, where the black lance had landed. The soulshard must've allowed Satan to teleport to it, bypassing Asmodeus's obsidian shield entirely. But instead, Asmodeus was more focused on the jagged sword impaled through his torso, right where his heart was. His body was too powerful and well-built to die simply from the sundering of a organ that pumped blood, but losing such a vital organ still made him violently spasm; soon he'd likely be too weakened to continue fighting. He thought of getting away, but then he felt the curved blade of Satan's scythe behind his back that would sever his spine if he tried, and a moment later Satan's whip twined itself around Asmodeus's legs and dug its thorns into his flesh. The axe was held against a side of his neck, and the mace above his head, ready to bash his skull in. For good measure, Satan's shadow materialized behind Asmodeus, the six serpentine heads spreading out to seal the route of retreat if there even was one, and numerous tendrils formed out of the blood that dripped from the Beast's armor extended to block off even the sides.
"I win," said Satan, his voice still perfectly even and smooth despite his current monstrous form.
The Crimson Fiend said nothing. There was nothing he could say.
"To any and all who dare to challenge my rule, allow me to remind you that I am God, and this world is mine to do with as I please," Satan's voice boomed across the arena, to all the demons that were watching. "And unlike that pretender up there in his so-called Heaven, I am a fair and just God. Serve me well, and you shall be handsomely rewarded. But rebellious subjects are not useful to me, and will be crushed without mercy, like this wretch before me." He spat on Asmodeus's face, and the younger demon felt the caustic liquid's sharp sting, before Satan dissolved his soulshards and allowed Asmodeus to crumple to the ground in a bleeding, broken heap.
For an instant, Asmodeus felt an all-consuming rage within himself, a desire to sacrifice all of his body and soul in a titanic explosion, as a final act of spite. Even if his strongest normal attack failed to wound Satan, an attack fueled by the very power of his whole existence must perform differently... But no, that would not do. His power still had much room for further growth, and Satan could not have been that much stronger than him. So he suppressed the burning fire of his rage, and held on to an ember of it deep within himself. One day, he would learn of all of Satan's secrets... And then, Satan would be the one crushed beneath the feet of Asmodeus, the ruler of all that is and will be.
As Asmodeus opens his eyes, he smiles. Oh, how glorious it was... Even a century after, his heart still flutters with excitement when he thinks back to that moment, when he finally was able to destroy the enemy that he hated and despised with all his being. Yes, his heart, now made of molten obsidian, after his former heart of flesh was torn to shreds in his duel against Satan so long ago. The wound could have healed, but never did, as he instead filled it with black stone as a reminder of his terrible failure, and of his vow to make Satan pay for his impertinence... It was not easy, arranging for every single demon prince to unite against Satan, for Satan's words were far more trustworthy than those of the demon princes, who even now must be each plotting their plots that would grant them control of the Infernal Legion. But no matter. Soon... Soon, the Horsemen will be complete.
Yes... Sometimes, the humans manage to produce some truly fascinating ideas. A laughably inaccurate transcription of the Celestiarchy's teachings, the human Bible speaks of the four Horsemen of the Apocalypse, harbingers of true ruin that will spell the world's end. Regrettably, such beings never existed in Hell's history... Until now. Satan had been a fool, forbidding the extraction of energies from beyond the sealed Abyssal Gate, for its supposed "dangers". With Satan out of the way, and Asmodeus's ascension to the throne of the Prince of Darkness, he was finally able to take the true power of the Abyss and forge it into the gestalt ultra-demonic entity sleeping before him. War, Famine, Pestilence, and Death itself... A single component of this superweapon is more powerful than any spirit in existence, he's sure of it, more powerful than even Satan himself. Though he does not understand the inner workings of the eldritch energies powering this awe-inspiring monstrosity, it is still made to obey Asmodeus and Asmodeus alone. Soon, he will be unstoppable.
And the world shall bow down to him.