Honkai Star Rail - Isekai'd With A Stellaron Within

*oh boy, I think I cooked myself a little. Hopefully you'll enjoy the chapter. Let me know what you guys think. Peace out and Deus vult*

Far away in a secluded room, dimly lit by the glow of a few screens, was a woman who had chosen to look into something herself. One of her puppets had found an interesting subject, someone tied with the infamous Astral Express. Just a simple boy at a normal glance, yet the things inside of him brought about questions like never before. It wasn't just one, like Stelle, but three different Stellarons, one of which was abnormal even by their own standards. 

"Hm, these readings are surprisingly normal for the 'revenge' my puppet took on him. Such a petty thing to simply aim and try to fry his mind for insulting the Simulated Universe. And yet, he survived in spite of the circumstances." 

She kept looking over the numbers, the images recorded fresh on a nearby screen. She could see the creature, feel its gaze upon her, even if it was all just an image. 

"What an ugly thing. I do wonder how it took life inside your mind, Mark. You're an interesting test subject indeed. To think you even had the courage to ask for payment, and a rather big sum. You don't play fair, do you? One hundred years of training, that's what you asked for..." 

Her fingers tapped on the table, stealing glances on all the screens, watching the numbers change and evolve until they spiked, keeping watch over the scene as well in that time. She was amused by the situation. 

"...yet you received so much more training. You're truly 'lucky' that wiping your memories worked, even if it still affected your brain to a certain degree." 

She stared at a specific reading, satisfaction pooling in her mind as she kept untangling the knot of what he was—the knot that kept his being a secret so delicious. 

"That strange reading... it's a weird form of Abundance. That kept your mind working, making sure your brain wouldn't get fully destroyed by the forced mental aging. Truly astonishing. Ruan Mei would probably enjoy you as her lab rat." 

She kept staring over the monstrosity that appeared in the Simulated Universe, marveling at how it was able to take over the computer itself, rendering outside interference useless. 

"Your reckless plan ended up bringing it to life sooner than it should have... but maybe it was my puppet's interference that led to it happening. After all, your 100 years of training were turned, as a mere way to get petty revenge, into 1000." 

She hummed softly, a soft smile dancing on her lips, curling them up in a soft motion. Inside, a spark was ignited, one that wished to dissect Mark and figure out his inner workings to their core. 

"He went ahead and trained for a thousand years," she said, checking some other readings on how much his reflexes had improved. "It seems to have paid off. So, prove yourself, Mark. Show everyone what you have." 

................................................................. 

Reason was not needed much in the battle, not when all he could feel was the pain of moving, the pain of his lungs pushing against pained ribs with each heave, with each breath costing more than the last. Still, he fought, raging through the mess like a burning fire, the Fire of Will lighting the area with an even sharper crimson than the flesh-engulfed Stellaron. 

His voice rang out, doubled down by a lower version of itself, turning the once human Mark into a being of horror just like the one he was fighting, the red strands that flowed out of the helmet dancing valiantly with each swing of the sword. He used it with the left arm, since his right was nothing more than a chunk of ice tied to his body, infused with energy so he could move it. It was more than enough to tear his enemies to shreds, the claws in his armor sinking with ease in the dark goo, tearing it apart with the power of Will. 

"You still stand against me? Do you not realize the effort is futile?" the giant amalgamation asked, the voices coming from all around him. He didn't bother answering with words, instead setting the flames alight, burning all around him as he made his way to the center where the Stellaron resided. 

The flicks of his muscles were enough to send the sword flying in from all directions, cutting apart whatever was thrown at him. Tentacles tried to grab him, to crush him, to stab him once more, but most of them didn't even make it to his armor as he spun around, his body covered by the afterimage burning into existence. 

He grabbed, tore, threw, cut, and fought off with all his might, not tiring in his one-man stand. The power kept him moving, the Stellarons burning inside of him at an output far above anything he thought he'd get to use so soon. That one percent above half was vast, tremendous in comparison to the first ten used together. Herta was right with her measurements. 

"I shall bring you down, you hear me?! I don't care what you say, I don't care about anything other than making you pay!" 

The anger in his tone was palpable, spreading into the night with ease above the other sounds from the beasts he kept cleaving. It was rage that moved in his veins and bitter hatred towards himself for having to lose Himeko before his very eyes, even if she had become part of him. The heart molded into his armor from the bits of her sword was enough proof of that. 

"Foolishness, human. It is time I show you why you're worthless in front of true nothingness. Feel how deep your own mind can go, and succumb to the pressure." 

The entire city had been cleared out at once, the sea of flesh retreating with a strong pull. He stood alone, watching from afar as it all mashed in one large chunk in the center, and the figure grew up in size until it was the size of a building. Sunday's form was nothing but a mere toy in comparison, easily crushed by the monster before him. 

Mark looked up, dismissing his sword for a moment, feeling the coldness of his right 'arm' as it simply filled in the armor, allowing him to move somehow. He braced himself, watching the color return to the city as the Stellaron was buried so deep into the center that its light was barely visible. 

"Witness the darkness within you... the darkness that lingers inside everyone... that's what you're all feeling in this moment, helplessness, nothing but a crushing sense of agony at your impending doom." 

The red strands atop Mark's helmet dangled softly, rocking back and forth as he looked up to the creature of nightmares, the eldritch horror twisting and shifting before his very eyes, covered in more twisted limbs than one could ever see. Large tentacles sprawled out, with wide mouths open on all angles, all of them squirming in the air, dangling as eyes grew on them, staring at none other than Mark. He simply scoffed, playing off the pain in his body as he stepped forward, walking slowly. 

"When a boss enters their second phase, it means I'm one step closer to killing it. Bring it on, Will of the Cancers..." he laughed, his voice low and cold, doubled upon itself with a crueler echo. "Rip and tear until it's done..." 

Mark sent himself flying, the red flames bursting at once as he took to the skies, his face covered by the helmet, his eyes hidden beneath. He reached out, putting his palms together, dodging the tentacles that came at him and kept sprawling out, multiplying on the go to try and latch on to him. Two large jaws grew out of it and tried to swallow him whole, but he didn't care. He kept his palms together, prepared to fire the one strike that he nearly used against Sunday. 

"It's time for the special, huh? If this doesn't work, then I think I'm fucked." 

He spun in the air, his armor covered in flames as his body was propelled at all angles, speeding up more and more, dodging the storm of limbs. He kept his palms together, running as much energy as he could in them, gathering it up as fast as possible without actually killing himself in that moment. 

"Come on, come on... I just need a 51% blast... more than that, and I'm sure I'd end my days in this very second..." 

He kept twisting and turning, glad that he didn't have a stomach in that moment; otherwise, he'd have puked out the thing itself. He spun and spun, twirling in the air, moving to find an angle as he had finally charged all the needed energy. It was his own Will, mixed in with pure energy from the Stellarons. It was all a gambit on things he knew and understood of concepts. Nihility could be somewhat stabilized through sheer willpower, like in Acheron's case. His Sword of Will could cut through the creatures while seemingly burning them. It was a battle of concepts at that point, in their own right. What could resist Nihility if not the Indomitable Human Spirit? 

His body dodged more strikes, fleeting on a whim, turning, dodging, simply staring as the creature tried to drag him into itself to stop his efforts, He dove straight down, taking a sharp turn until it was in its middle, right above the Stellaron. He needed to be careful lest he blow up all of Penacony. Thus, he aimed higher than it, trying to create an opening to the core. 

"Time for the fun stuff, bitch..." he smirked, aiming his palms at it, keeping them together, open, and ready to fire the beam of energy. He chuckled, shouting. 

"Get nuked, bozo!" 

The energy went out at once in a crimson red pillar of destruction, razing the top of the creature instantly, yet it also sent Mark into the ground from the recoil. He was crushed by his own strike, but the armor could tank most of the harm. He simply aimed, keeping his arms from lowering to the 'bomb'.

The blast went off with a strong aftershock that rattled the entire city, throwing away objects that were close, causing even the ones watching to be staggered by it despite the barrier that they still kept up. Windows shattered while cars were pushed back. From the skies, an explosion somewhere far in space where the blast must have landed. Still, the upper half of the thing was erased, no trace of it left. 

He stood up, wasting no time as he made haste for the nearly revealed core, bursting forth with all his might, yet the sudden flash of tentacles leaping at him from all sides put an end to it. He tried dodging, but they whipped at him in swarms of thousands, blocking his vision, crushing him to the ground. It couldn't fully rebuild itself, but it did twist into a smaller version, hiding the Stellaron deeper within. 

"Fool until the end, fighting a losing battle... no worries, your despair shall be tastier..." 

It brought him up in the air, holding him tightly within the goo, trying to crush him, yet the armor didn't give too much leeway, standing its ground against the creature. It burned its flesh slowly and painfully. 

"Yes, succumb to despair, feel it curse through you." 

Mark tried to free himself, but he lacked the strength to do so. He pushed as much as he could, but the flesh would just pile up in waves, trying to crush him. The Indomitable Human Spirit would one day die out with the universe, that was his mistake. He overlooked the limits of humanity—time itself. It's the same reason some theorized Black Swan ended up on the path of Nihility, thanks to Acheron showing her that memories would one day be turned to a void, turning her entire purpose into something useless. It's the path that got even Acheron to succumb to it, even if she was strong enough to fight until it was just her left. Her will was far stronger than his, even if Himeko boosted it with her own being. 

"I... I see... haha..." he erupted into laughter, shaking his head as the creature sought to devour him. He was laughing at himself, at his own stupidity, at how he missed the whole point by a lot. His Will could be molded, yet it allowed Himeko's will to shine through with his own. Why not allow that of others? 

"Heh, I see..." he whispered, focusing on one last effort. He burst out in flames, the explosion causing the flesh to pull back just enough for him to get out, speeding up to the skies with all his might. 

"My Will in this very moment is to show to the whole world what I follow!" 

His voice carried over the city, reaching the ears of the group, who was watching with worried expressions as Mark sought flight for the thousandth time. He kept going, higher and higher, bits of his armor falling and vanishing in the air as he kept pushing. 

"Acheron, make sure you're watching! Black Swan, you too, you crazy woman! Welt, you're in cahoots with Nihility too, so keep your eyes peeled, all of you!" 

He reached higher, moving away from the tentacles that were slowly losing ground. His right arm shattered, the ice unable to hold anymore. The bits that kept his stomach together held on, the armor glued in place by the heart-shaped fragment. He brought his left hand up in the air, holding it out. 

"I shall have the world bear witness to the Truth... if my Will can be shaped, then let it be shaped upon this ideal. God, bestow upon me a spark of Your Light, enough to cleanse the evil before me, evil born out of myself." 

His hand remained outstretched to the very heavens, his gaze fixed up, despite the tentacles reaching closer as he halted his ascent. He had to place his faith in it, to truly believe and not waver. He could feel them come closer, closer, bit by bit. 

"You cling to hope until the last moment like a drowning animal! Let go and join me! Become one with me fully! Embrace me like I had embraced you in the darkest nights!" 

The voices rang out loudly, but Mark did his best to keep looking up. His hand felt empty until something soft touched it. In an instant, the Light lit up the universe itself, spreading out fiercely. It didn't burn, it didn't hurt, but it was heavy, yet Someone held it in place, allowing him to use it. His eyes went down at the creature, but he didn't address it. He just watched the tentacles burn for good, turning into smoke that went out under the pure white Light. 

"Welt, there is hope no matter what circumstances we're in. Black Swan, your memories have a place to go to, a place where they will exist eternally, no matter what happens to this world. Their story will persist into infinity and beyond..." 

He clung to his consciousness, speaking the next words loudly, pouring his heart into them, conflicted as it was. 

"And Acheron, this is the light that no Nihility could even manage to hide! You seek the light beyond IX, but this is Light that no darkness could ever hope to hide! This is what you should find at the end of the journey. This is pure Salvation." 

It increased in intensity, covering the world, reaching worlds that were countless ages apart. In that moment, Mark smiled, thinking of everyone as he shouted. 

"Primordial Spark...Divine Purger!" 

Everything turned white as he swung down, their visions blinded but not pained. In that moment, nothing else could be seen, just for those few seconds. The sound of the voices dying out rang loudly, but it all faded into nothingness. 

As soon as he could see again, he dove down for the Stellaron, which was in the middle of a pool of liquid, white like milk, but hard as he stepped on it. He didn't focus much on it, instead walking to the Stellaron, ready to put an end to the show. 

"Thank you, Lord... now I should end this farce..." 

He reached out, ready to grab it, but something else snatched it away, musical notes covering it. He was too tired to fight again, too tired to do anything else, yet he could see it. The city vanished, and he found himself in a dream, standing face to face with THEM. 

"Oh, you who brought harm upon my children, how should I punish you?" 

He stared at the being before him, watching as a single face looked his way, the white hair covering the other two partially. Puzzle pieces floated around, fixing in her body before another one would leave and twirl around. He noticed it somehow—the subtle pattern in which they moved—a harmonious melody in itself. They moved around before crashing in the same, calculated motion— didn't know it too well to guess it at a glance, but the path each puzzle piece took was akin to that spiral, so he guessed it to be the perfect one. the golden ratio. He didn't know it too well to guess it at a glance, but the path each puzzle piece took was akin to that spiral, so he guessed it to be the perfect one. 

"Xipe, aren't you?" he asked, his tired voice ringing out with what little fight was left in him. 

"My, so hostile, child. I see that you wish to take this," THEY sung, the sounds touching his ears like a blessing in his battered state. THEY brought the Stellaron forward, and he tried to reach out for it with his left hand, yet to no avail. 

"Great... I gotta stare at your mug too..." he sighed, already fed up.