The soul parasite came to Usain two hundred years ago. It came from the space between stars while leeching off of that divine monstrosity, Phegmehogal.

It was a fundamental law of nature that each creature could only contain a single soul, but the space between stars cared little for the natural laws. Vast and boundless entities lived there, hosting vast and endless souls. Something small like the soul parasite could chew away a little space for itself and reside there.

The soul parasite witnessed Phegmehogal’s invasion of Usain, riding along during it. He saw the Evil God’s glorious rise and meteoric fall. And when death seemed to be upon his host, the soul parasite fled.

It hid in the body of a beastfolk corpse that had fallen on the final battlefield, bringing its body back to a semblance of life with magic.

But the beastfolk body resisted the soul parasite’s magic, continuing to slowly decay, and so it was forced to change hosts often. It dwelt beyond the confines of ordinary society: among bandits, where morality was in short supply but the potential hosts were endless.

The soul parasite had an ideal host in mind, and it wasn’t a short-lived beastfolk corpse puppet. It bided its time and waited for any opportunity to claim its perfect vessel.

One day, the bandit group which the soul parasite had infiltrated attacked a caravan of dwarf slave traders. Among their slaves was an elf. The soul parasite killed the elf in the chaos and claimed his body as its own, then it joined the beastfolk in their fight and they drove off the dwarves together.

It was thus allowed to join the bandits in its new body as well.

The elf body was a great improvement. It handled mana much better, and so it would last much longer before breaking down. The soul parasite had the leeway to occasionally leave for a few days, enter a town, and investigate methods to put its grand plan into motion. It learned about mind casters and mind stones, about dungeons and creature cores, and it learned that it wasn’t the only being that had learned about these things.

The soul parasite fled again from organized society and its threats, forced to rely on luck. All it could do was hope the stars would align before its current convenient body broke down.

When a young demon man joined the bandit group, the soul parasite thought it was lucky. He could act as a reserve body in case of an emergency. Two years later, another demon joined, a woman this time. The soul parasite felt spoiled for choice for a change.

Best of all, now it had both a reserve body and an extra that could potentially become its ideal host.

The soul parasite did not have an ordinary mental structure, given its nature and origins. No matter how much time it spent together with the people of this world, it didn’t grow fond or attached. It only conducted itself in a way that mirrored the behavior of its local hosts, to the extent that its true nature and goal wouldn’t be discovered.

Dying in a dungeon wasn’t part of its plan. It thought everything was under control and its host was safely at the backlines, but a misfiring trap of all things caused a fatal injury, and it was cast out. Of course, it could have simply entered again before the dungeon absorbed its host, but that would expose it for what it was.

The soul parasite was barely able to hold out without a host long enough to escape the dungeon, inhabiting a dead rat of all things once it had escaped. It rushed to follow the survivors, intent to be there the moment the bodies were resurrected, but it was late and very unlucky. All but its previous host were already occupied by their original souls again.

The soul parasite cursed its foul luck for not being there sooner and quickly inhabited his old host before the facsimile of life it had programmed into his mind stone could run out and reveal him to be a mere copy of a corpse.

The only good news was that it was easy to get the foolish meat sacks riled up for revenge. Yarnam just had to stay behind this time.

After a few days, it was clear that they were all dead once again. The soul parasite’s goal was just a resurrection away. But now the nearest mind caster was under watch, and he couldn’t risk using it.

While the soul parasite waited in a nearby bandit camp for things to calm down, a golden opportunity came to it in the form of a purple slime. There was an obvious creature core suspended in its body, which meant that it belonged to a dungeon.

Since the soul parasite was in need of a resurrection mechanism, it pretended to be sleeping in the middle of the day and let the slime take the mind stones away. Then it abandoned Yarnam’s body for a dead bird’s and flew after the monster.

The moment that the dungeon returned one of the mind stones to the gate guard was when the soul parasite learned the female demon’s last name and her true identity.

The gate guard’s arrival was bad timing, and the dungeon’s behavior was outside of the soul parasite’s expectations, but there was still a chance that it would experiment with the mind stones it had recovered. Even if it made a public show of destroying them, they weren’t really gone. The soul parasite had faith in a dungeon’s curiosity and in the demon god Bath’s madness, so it flew back to its primary host and started the long journey to Erakonir.

It had every hope that it would find there a living demoness of an influential family whose body was a soulless husk fit for inhabiting.

And it did. Though inhabiting a living body presented new challenges that the soul parasite wasn’t expecting. The mind of its new host was still intact, so as the soul parasite attempted to mold its new host in its image, its host also molded it. If it was too slow to act, or encountered too much resistance, it would cease to be the being it once was.

When the soul parasite noticed this danger, it actually tried to pull away, thinking of approaching again later when Casanuella was sleeping and reshaping her mental structure to match its soul would be easier. But its new body had already partially acclimated to it and refused to give up her new soul. The soul parasite was trapped, and its host was trying to kill herself.

The fear induced by that unexpected complication was extremely motivating, and the soul parasite fought with everything it had to keep its host alive and to not be erased.

And it failed, Casa summarized, drumming her fingernails on a wooden tabletop. And so did Casanuella.

She was seated in the quiet darkness of her room, contemplating.

The new Casa was a being that, as far as she could tell, contained the memories of both of the original beings that fought for her body. She was recollecting now as much as she could from each in order to decide how to proceed.

The knowledge that she, as an entity, was a combination of a young demon noblewoman from the shell of the great demon sage’s family and a parasitic spiritual entity that had come to this world riding the Evil God’s coattails surprisingly wasn’t incongruous to her current self at all. She didn’t feel the need to reconcile whether she was an alien being to this world or not. It wasn’t important.

And my spiritual forbearers aside, I think it’s fair to say that I was born here.

Speaking of the new Casa’s forbearers…

The soul parasite had been sly and driven, with mystical powers, but it wasn’t particularly smart or capable. It wasted two hundred years just trying to find a proper body. As highly as the otherworldly being thought of itself, the new Casa did not agree.

Meanwhile, the original Casanuella had been smart, well educated, and magically powerful, but she was unmotivated; aimless; a rebel without a cause. The new Casa thought that she, too, had been a waste of centuries.

The new Casa believed that she shared both of her progenitors’ knowledge, ability, and drive, and that she should be capable of succeeding where they failed.

You could be reading stolen content. Head to Royal Road for the genuine story.

No, I must succeed, she thought.

The soul parasite wasn’t wrong for avoiding organized society—especially demon society. There were people in the know who might be able to detect the anomalies in her soul. Before that happened, she had to become too valuable to destroy.

Not that I needed more excuses, she smiled coldly, to kill my parents.

***

For the next week, Casa was the picture of a dutiful young noble from a scholar’s family. The entirety of the great demon sage’s literary collection was within her grasp, and she devoured it gluttonously. She had a gifted mind that absorbed the contents easily, which she hadn’t been motivated to properly use since childhood, when she realized her family’s pathetic reality and gave up on wanting more.

Wouldn’t the great demon sage find it a terrible waste if he ever did return?

Do people put the cart before the horse because they’re foolish or because they have no destination? She reflected briefly on her own lives. Either, I suppose.

Of course, this change in attitude didn’t go unnoticed by the family and servants. Casa’s parents didn’t care as long as she was behaving and adhering to the rules they had forced on her. The servants didn’t think it was their place to ask about it. But Casa’s younger brother confronted her with eyes full of suspicion.

“Why are you studying so hard?” he asked, taking a book off the pile. “You’re not thinking of becoming an herbalist or a doctor, are you?”

The gathered tomes trafficked mainly in internal medicine.

“A new interest born from being around death one too many times,” she justified.

Casa’s brother scowled at her and turned away, folding his arms. “It would have been nice if you found this motivation before running away.”

“Did mother and father put their focus on you while I was gone?”

“What do you think?”

Casa smiled at her younger brother. “It’s because they’re small people that they’re terrified of us,” she said. “They’ve been leeching off the government for centuries using our ancestor’s name. Their only job is to raise us well, and if they fail, their entire way of life will collapse. We have the ability to ruin them.”

Casa’s brother, Frazar, looked at her curiously, considering her words in all seriousness. She turned her eyes back to the text she was reading. “We can. But I no longer want to ruin myself just to drag them down with me. Freedom was nice, but I’ve had enough.”

Power is better and will free me all the same.

Frazar clenched his fists, said nothing, and departed, leaving her to read in peace.

In the silence that followed, broken only by the crisp sound of turning pages, Casa found what she had been looking for all these days; a simple combination of common herbs that had the effect of weakening a demon’s heart when over-consumed.

It wasn’t nearly enough to cause the heart to fail, even then, but the heart was a very important organ for demons for another reason besides its use in circulating blood.

Casa searched their selection of cookbooks next, doctored the quantities listed for one recipe that suited her purpose, and ensured it ended up in the kitchen.

Then she just had to wait until she tasted it on her plate.

***

“I hate books,” Frazar confided in Casa one morning. “And I hate our parents. I’m thinking of sabotaging them, but I don’t want to run off and join a group of bandits, no offense.”

“None taken, little brother.”

Frazar leaned closer and lowered his voice. “How can I screw them over while succeeding for myself?”

A smile bloomed on Casa’s face. Frazar wanting out of the house of scholars was positively serendipitous for her plans.

“Join the military,” she told him. “If you succeed there, you’ll have honor and prestige. There’s always rivalry between scholar and military houses, so mother and father will throw a fit.”

Frazar stood up and nodded his head. “Got it,” he declared, and left her alone.

Casa heard rumors of him practicing his magic and weapon skills in the following days. She didn’t exactly expect her brother to thrive in the military, especially not when the people there would be prejudiced against him for his family name, but if he happened to have talent, all the better. Of course, that would have to wait until he was old enough to actually join, and that wouldn’t be for another two decades when he turned a hundred and fifty.

What came much sooner was a delicious dinner composed of bird meat and a healthy helping of vegetables and spices. Casa ate every bite and glanced around to make sure her parents did the same. She mentally set a timer for when the food would be digested and its effects would begin showing in the body.

When she had a chance, she excused herself and went back upstairs, but not before passing by the scullery and collecting a few things. Many edible plants were useful for more than just eating, and one could do wonders quite quickly with a needle and thread and a few small alterations.

For the next two hours, Casa sat alone in her room, raising the hem on her skirt, and cutting swaths of fabric from her shirt. Time was short, and it was a rushed job, but all they needed to stand up to was the initial reaction.

She redressed herself, and her long skirt now rose halfway up her thighs—with the leggings discarded. Her shirt did nothing to cover her back or neck and dipped into a deep V at the front. She kept the long sleeves attached only for structural integrity. Then, with some red vegetables, she stained her lips, cheeks, and eyes. The effect wasn’t bad at all; classy and very bold, but it would last less than an hour in all likelihood.

Casa felt a prickling heat in her chest. The ingredients from dinner were working to weaken her heart, and so her mana wasn’t being suppressed as well as usual. It circulated throughout her body in an angry fizz and finally reached her brain, where it set all of her hormones and emotions on edge.

Casa took a deep breath to consciously calm herself and smiled at her reflection. All preparations are in place, she thought eagerly.

Her plan was quite simply to anger her parents to death. They were already well-known for their poor tempers. Who would doubt it if they exploded one day? But despite her thorough preparations, she barely got to the top of the stairs before she witnessed an argument in the foyer below.

“Brat! I dare you to say that again!” her father shouted, red-faced.

“I said I quit!” Frazar shouted back, gripping a dull metal training sword in his hand. It seemed like her parents and her brother happened to pass each other while the latter was on his way to train. “As soon as I can, I’m leaving this house to join the military! That stupid sage is never coming back, and we should all just move on with our lives!”

“How dare you!” Their mother exclaimed.

“Why, you ungrateful—What use do you have aside from your family name?!”

Casa saw veins swelling up on her father’s neck and forehead. The three arguing were too incensed to notice it, but all three were showing warning signs of mana explosion.

If the servants came by, they would certainly notice it and try to calm everybody down—by force if necessary. So Casa silenced the foyer.

This is fantastic! she thought, dashing back to her room. At this rate, they’ll blow up even without me.

She couldn’t afford to be implicated in her parents’ deaths if she wanted to succeed her house, so the less involvement she had, the better.

Casa skidded to a halt in front of her wardrobe and yanked a cotton bath robe out of it. She threw it on top of her slapdash ensemble and splashed her face and hair with water magic, both to wash away the homemade makeup and make it appear as though she’d just come out of the bath. Then she ran back to the foyer.

The argument had mounted further even in the short time she was gone.

“Well I’ve always hated those moldy old books!” Frazar shouted.

Their mother screamed back at him, “Maybe if you weren’t such a witless failure you could appreciate them! Even your whore of a sister isn’t such an idiot as you!”

Frazar gripped his fists and stared at his mother with bloodshot eyes. “I wonder where Casa got it from? Maybe I’d be smarter if my father was from a scholar family.”

Their mother stepped back like she’d been slapped, and Casa’s father turned to look at her with fangs clenched tight. “Euria?” he asked with a voice full of venom.

“It’s a lie!” she cut her hand through the air, wild-eyed. “The bastard is lying!”

“Bastard?!” Her husband grabbed her by the collar of her dress and pulled their faces close.

Casa’s mother pursed her lips tightly. Cornered and with nothing but blind rage controlling her now, instead of speaking words, she bit his nose with her fangs. He beat her off of him in return, and after a short and violent scuffle, their bodies swelled with black light and exploded in a fountain of blood and viscera.

Casa consciously held back her laugh this time.

“Brother!” She called from the top of the stairs, choosing that timing to dispel her silence spell and descend. “Are you alright?”

He was standing still when she reached the ground floor, staring at the pool of blood and trembling. Casa, who was half a century his senior, placed a hand gently on his shoulder to comfort him as an older sibling should.

“I heard arguing so I came over. Take deep breaths now.”

Frazar followed her advice as best as he could, trying to go through his calming exercises while hiccuping. It was made harder both by trauma and the drugs still in his system.

“How much did you hear?” he asked her.

Casa looked down at his teary, bloodshot violet eyes and pulled her little brother into a hug. “You’re my brother,” she said.

He teared up more at that and buried his face against her shoulder. The sound of sobbing broke up his words. “I’m sorry. I didn’t mean to call you a whore. And I didn’t mean for things to get this bad.”

Casa nodded and stroked his snowy white hair. “They deserved it,” she assured him.

Frazar continued to cry, and Casa gave him a few moments before holding a hand over his head. “Rest and calm down, brother,” she declared, and cast a sleeping spell on him.

Frazar went limp in her arms, and she passed him to a servant. They had come in response to the sound of the youngest crying.

“Take him to his room. Make sure he’s able to calm down when he wakes up.”

“Wh-what happened?” A servant asked, peering at the blood with wide eyes. He hurriedly tacked on a “my lady” when it occurred to him that Casa was his new employer.

“Father discovered that mother was being unfaithful,” she said simply. “Please fetch someone to clean up this mess and send someone to meet me in the study. I’ll have to let the government know that I’ll be succeeding my house. Oh, and call a funerary priest, I suppose.”

“Yes, Lady Opherion!”

The servant bowed and went to do his work. Casa took a moment to stare at the pool of blood and smiled contentedly.

With the house under my control I can finally move on to the important things, she thought, departing back up the stairs. Like becoming a god, killing my neglectful ancestor, and wiping out dungeon kind… Hm. Perhaps not in that order.