This was a multi-day project... Taken from Echos of Eternity
The angel and the demon meet in the air beneath the sky the color of blood drawing breaths that taste of murder the first impact of blade against blade is a metallic thundercrack while their sons wage war below fighting and dying in the shadows of their father's wings the lord of the red sand swings and the black blade shrieks it's steel flattened on souls but the angel is gone twisting away soaring higher angron beats his wings giving chase enraged at his own cumbersome strength it's like fighting a shadow each time he closes on sanguineus the angel rolls aside or furls his wings and drops away each missed swing of his sword each failed grasp with his talons resonates inside angron's skull with a splash of acid the nails bite to give him strength this is so but they also bite to punish him now more than ever the nails bite the sound of horus's urgent command begging for the angel's death angron what little is left of angron now that his soul has been transmogrified into the flesh matter of an ethereal god has never heard horus beg before the weakness in the war master's voice makes him shudder with revulsion sanguineus dives low swooping toward the ground and angron follows volkite beams stab up at them glancing the sky they fly through detonations that blacken the angel's armor and darken his wings explosions that do nothing but tighten the demon's hold on incarnation every death taking place upon this planet every life ending beneath them strengthens angron and seals his wounds closer he comes closer he can smell the sweat on his brother's skin he can hear the drumbeat of his brother's blood he can smell the sweetness of the angel's wounds sanguineus senses it the angel veers away with a grace angron cannot hope to match a spread of feathered wings arrests his dive and a slash of straight silver rips across the demon's face there is no pain most of his face has been cut from his skull but there is no pain he experiences pain the others might feel grief or trauma or frustration to him it is a helplessness a wound within it is something that cannot be tolerated something that can only be overcome with the running of enemy blood he's blind his face broken by the silver sword and without the organic receptors to process injury it's the weakness that hurts his eyes regenerate as he thrashes blindly with his blade he can see again dull and dim for another few moments then with a clarity that defeats the ash and the dust swirling in the air he doesn't see as a human sees angron sees the fire of souls and his brother's flares brightest of all when they meet again it's in a killing embrace the lord of the red sands tears the angel from the sky clutching his golden brother in his great claws bearing sanguineus down they fall and fall and fall and crash through the galactic dome of the martian temple atop the warmonger titan malox meridius they strike the floor in a role that would break any immortal bones their tumbling bodies obliterating the mosaic rendering of the opus machina sacred icon of the adeptus mechanicus and the martian mechanicum alike this is a sacrilege neither brother notices tech priests and menials flee the dueling demigods neither of them notices that either angeron gets a clawed hand around the angel's head he beats sanguineus's skull against the floor once twice thrice and cracks web out along the tiles and stone splitting veins a fourth time a fifth there is weakness then perhaps it should be pain as well but it is most definitely weakness angron's grip slackens his arm dissolves literally it dissolves from the shoulder down and the lord of the red sands is thrown back as the angel rises in sanguineus's hands is a pistol and the dregs of anger on sentience recognize this as the melta weapon in furnace a one-use thing of incineration the angel casts it aside and takes wing diving right at the demon leading with his sword anger on raises his own blade feeling the flow of the incoming blows like promises whispered in warning and he catches each of the angel's thrusts before they can impact against him metal grinds sparks spray arcing out from the meeting blades hypnotic in their falling beauty for a moment just a moment he is on the plains of des region camping rough beneath the pale moon watching fireflies play above the banked campfires of his freed slave army how peaceful that night had been even with the nails and knuckling into the back of his brain how peaceful that one night was before the emperor tore him away from his real brothers and sisters the siblings of his heart and not of manufactured blood leaving them to fight alone leaving them to die leaving him to face this unwanted life and sanguineus impales him a lance of ice runs through where his heart should be the two brothers are face to face one of them a visage of bloodied human perfection the other a construct of absolute inhumanity rage made manifest as close as they are despite the changes to anger on division he sees the tiredness etched on the angel's features the faint cuts and scratches that the battle for terra has written on the sanguineus's flesh indeniably marking him this war has rendered the perfect imperfect die sanguineus tells him with the gentleness of giving a great gift i free you from this torment anger on his lips peel back in the memory of a smile he tries to speak speaking is difficult not because he is dying but because he is no longer a creature for whom speaking is a natural or a necessary process speech is an echo from a lost life the lord of the red sands expresses himself in slavering roars and the death of his foes sanguineus sees this sees the way anger on his face twists trying to remember how to form words sees that the demon is not dying the lord of the red sands moves but the angel is faster sanguineus tears the blade free and leaps upward taking to the sky bleeding laughing the demon follows they swoop between the temple towers that rise from the black of malik's meridius they break away into the open sky sanguineus is slower in the open but he is built for this he is graceful and experienced and born for aerial warfare anger on has the unreal strength of demonic muscle but he is a gargoyle chasing a hawk sanguineus weaves and soars and dives out of his clutches and horus inside the demon's mind the words are bloated by the pantheon ripe with the borrowed power of the gods behind those words is the promise of pain true pain nails pain the lord of the red sands beats his wings harder his sword leaving a trailing wake of screaming souls the dead of terra singing their song they race low to the ground hardly in arms reach above the heads of their warring sons fast enough that their armies are an indistinct blur anger on swings the black blade he gouges earth he sends blood angels and world eaters tumbling across the ground their bodies destroyed their souls spilling into the warps millions waiting maws without warning sanguineus climbs soars this is your chance remember the lord of the red sands ignores horus is pulling he senses sanguineus is tiring and sees it in the flicker of his soul fire his brother's spirit ripples with the desperate sweetness of exhaustion the war the battlement the bane of the ninth bloodline yes the angel's strength is running dry the demon gathers speed flying into the polluted wind while anti-air fire stitches the air around him sanguineus weaves aside from the blinding slashes of las cannon beams rolls away from the juddering passage of allegiance storm bird anger on far less maneuverable crashes into it goes through it tastes the flavor of those doomed souls as their craft comes apart around them it is nothing to him the expenditure of a breath's worth of efforts behind him the storm bird falls from the sky its hall of flame and cleaved into the largest piece of its structure will tumble against the side of the sanctum imperialis detonating against the thickest void shields ever created wreckage will rain upon the warriors of both sides anger on knows none of this will never know it do not fail me anger on the babbling of a frightened creature speaking as though it were in control the lord of the red sands pays it no heed they dive through the death cloud the falling titan into black smoke and the white fire of plasma the billowing smoke cannot hide the light of the angel's soul anger on is close close close enough that he parts his jaws to reveal uneven rows of mismatched teeth that jut up from bleeding gums as they circle in this burning choking sphere that only burns and chokes one of them the demon gives a draconic roar the sound is exultant and instinctive is unfiltered emotion and it wreaks more of triumph than rage anger on's mouth is still open when the spear hurled from the angel's left hand strikes it shatters most of the demon's teeth severs his tongue at the throat root and punches through the back of his head with the cervical segments of his spine reduced to ectoplasmic chunks anger on falls boneless stunned from the sky the angel twists in the smoke and follows his brother down anger on hits the royal ascension with cratering force at the heart of the two warring legions his impact kills almost a hundred warriors on both sides but this is another concern outside the shreds of his sentience the surviving world eaters cheer him through the dust then bay at him like loyal hounds but he knows nothing outside his own fury he claws at the spear he roars around its impaling length in these helpless seconds he is a beast stupid and sound and action thrashing into the dirt the lance comes free slick with icor pretending to be blood goblets of demonic flesh sizzling on its silver surface already the demon is reforming re-knitting sustained by whatever metaphysical processes fuel its existence the lord of the red sands throws the weapon away in time to meet its wielder the angel descends with a silence that stinks of false righteousness as though he were a creature too enlightened to feel rage the brothers collide in the crater they made around them the battle for the eternity gate rages the world eaters are coming the world eaters and the life takers and the blood letters sanguineous senses them drawn near hears their howling angron sees this awareness down in his brother's eyes sanguineous hacks and hacks and hacks as the snarls of chain axes and demon blades grow louder it isn't enough the angel launches away a crack of his wings carrying him upward the lord of the red sands knows he can't catch sanguineous in the sky he scrambles for the fallen spear draws it back and this time there is no chase this time angron is ready he throws the spear still slathered in icor from where he tore it out from his own throat the second he casts it it rips through the air with a concussive drumbeat breaking the sound barrier the angel rolls aside with the grace of the skyborne dodging this streak of bladed intent no angron sees not dodging faster than the human eye can follow the angel has caught his spear as it passed rolled with the momentum and now he casts it back to the ground with a cry of effort angron will catch it this twig of a thing and he clutches nothing but air and the force of a meteor hits him in the chest throwing him down pinning him to the warp stained ground for several unreal seconds the lord of the red sands is impaled in place speared through the chest there is no pain only humiliation he frees himself in time to see sanguineous ascending leaving him behind his wounds close but slower slower slower than before the nails bite harder despising his weakness angron turns his back on his brother seeking the lesser blood angels in the legion red he wades through them ending them sending their bodies flying back with heaving swings of his soul thirsty sword if he cannot catch the angel he will lure the angel back to him he learned this from the bane it takes no time at all angron has scarcely begun to shed blood before he hears the descending beat of angelic wings the lord of the red sands wipes the writhing bodies of dying blood angels from where they're spitted upon his blade and he turns to meet his brother once more bolt shells impact against him chainswords carve into the unmeet of his legs he ignores this the pitiful defiance of his nephews with their bolters and their chainswords he will kill them and devour them and offer up their skulls to the skull throne yes but now first the angel must die.