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The Tenth Mystery: The Demon Asta

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Turns out working for a ghost isn’t as supernatural as one would think. Yuno learns this with as much enthusiasm as he learns most things in school, which is close to none. Asta is a pain, pulling pranks on Yuno left and right and asking him to keep his bathroom clean on the daily.


Yuno wishes he could take back that day, the day Asta saved him by turning him back into a human, but... It was kind of his fault for doing something so stupid, so maybe this is his punishment for messing with the supernatural.




The student groans as he feels Asta run into his back, making him lurch forward. He turns to look at the ghost that’s supposed to be his “master” and wonders how this kid has such terrifying powers hidden inside him.


“What do you want?” He asks dryly.


“Aw come on don’t be like that! Why do you sound so mad?” Asta wraps his arms around his waist from behind. “Is it because I’m making you clean?”


Yuno doesn’t dignify that question with an answer, because what else would it be?! All he’s done since he met Asta was clean, clean, clean. He cleans during his school duties, he cleans after school when Asta tells him to and he cleans back at the orphanage when he leaves. He’s starting to feel like Cinderella at this point, but with the fairy godmother being the one making him work.


“Don’t be mad Yuno! Come on you can take a break!” Asta pulls on his shirt, and as much as Yuno needs the break he doesn’t want to give Asta the satisfaction of winning.


“No, I’m finishing this.” He says stubbornly, turning away from Asta.


“Fine! I’ll make you take a break then!”


That’s when Yuno suddenly feels himself being picked up, and he gasps as Asta begins making his way towards the stairs with Yuno slung over his shoulder.


“Asta, you have three seconds to put me down before I kick you where it hurts.” Yuno says through his glare, holding onto Asta’s back to keep from falling.


“You shouldn’t do that to your master Yuno! Because I could turn you back into a bird by accident!”


Yuno can hear the stupid grin in his voice, and as much as it irks him he knows he can’t really counter him in any way. So he let’s Asta carry him, blinking in surprise when he finds himself on the roof of the school building.


“Here we are!” Asta finally sets him down, walking over to the railing and hopping onto it.


Yuno follows, trying to keep his hair out of his eyes as the wind whips it around wildly. He rests his elbows against the railing next to Asta, looking down at the city just below them.


“Look I uh...” Asta starts before silence can settle over them, “Sorry about making you work so much, I guess I just kinda make you do it cuz I like spending time together with you.”


Yuno’s eyes widen at the confession. He’s only known Asta for about a week or two, but throughout that time the other has shown him acts of kindness one would usually reserve for a close friend or even a lover. He wonders why that is, but doesn’t ask, because it almost seems like Asta isn’t aware that he does this either.


“When we clean and chat together like this, I feel like I’m hanging out with my friends again.” Asta continues, a blush on his cheeks, “It takes me back.”


Yuno let’s his anger go, he smiles, “You don’t have to make me clean to do that you know. Idiot.”


Asta blushes and stutters, “Who are you calling an idiot you handsome jerk!”




“Why you-! Come here!” Asta lunges at him, but Yuno is too quick.


Yuno chuckles as Asta nearly falls on his face, running through the roof as the ghost follows him. He has to admit this is fun, as strange as it is, because no matter how hard he tries he can’t help but always feel at ease with Asta. It’s nice.




Yuno gasps as Asta does indeed catch up to him, wrapping his arms around his torso tight and knocking him over. They laugh, and when Yuno turns to face the spirit the other is giving him such a soft look that it takes his breath away.




“Hold it right there you fiend!”


And suddenly Asta is screaming, flames engulfing the ghost as he throws his head back in pain.


“Asta!” Yuno calls worriedly, but then someone grabs Asta and throws him out of his reach.


He looks up at the attacker, seeing wild orange hair that ties into a braid and blue eyes. It’s a boy, about his age, who wears the Crimson Lions’ uniform. That means he goes to this school too, but...


“Don’t worry, I, Leopold Vermillion have come to save you!” The guy grins back at him, holding a sword engulfed in flames.


Then he turns back to Asta, who’s getting back up. “Geez you didn’t need to be so rough! It’s not like I was bothering anyone!”


“Lies! You were attacking this poor defenseless student! And as an exorcist from the house of Vermillion it is my duty to protect him and put you to rest evil spirit!”


Yuno stares between the two of them, wondering if the nonsense this guy is spouting could actually be true. He did burn Asta, and even if he looked better now those flames seemed to have done some at least damage to him.


“Woah calm down buddy! I know you’re a Vermillion but let’s not get ahead of ourselves!” Asta raises his hands pliantly, “Yuno is my friend, I would never hurt him!


The statement makes Yuno’s chest warm, but he swallows it back without giving it much thought.


“It’s true, Asta wasn’t hurting me.” Yuno stands up, trying to step between them.


But the guy isn’t having it, he grabs Yuno’s arm and pulls him back, keeping him from approaching Asta. The other is an inch or two shorter, but Yuno can tell he’s physically stronger regardless.


“Don’t let yourself be fooled, spirits like him put people under spells and control them.” He glares at Asta, who looks just as angry. “Just look at the mark on his hand, that’s the mark of someone who’s been cast off to repent for all eternity.”


Yuno’s eyes drift to the mark on Asta’s hand. He’d asked about it previously, but Asta had said it symbolized his attachment to the demon inside him.


“I didn’t lie to you Yuno,” Asta is quick to say, as if he could hear his thoughts. Yuno doesn’t know why, but he believes him.


“That mark is only given to those who break the worst of taboos.” The guy raises his sword, “Like murderers.”


Yuno’s eyes widen, looking back at Asta and waiting for him to deny it.


“I didn’t kill anyone...” Asta clenches his fists, but before Yuno can relax he keeps going, “Yes I broke a taboo, but it’s not like you can understand why I did it.”


“I don’t really care why you did it, the fact is that you messed with the laws of nature and now you must pay the price.”


And then the guy lets go of Yuno’s hand,  when he looks up both he and Asta are clashing. Asta wields a giant black sword he’s never seen before, and the angry look in his eyes unnerves him. That look doesn’t suit him at all.


“Let him go you devil!” The guy shouts.


“No!” Asta bites back.


They pull away and clash once more, their swords sending sparks flying every which way. Yuno huffs and looks around for anything he can use to stop them, cursing when he’s met with only the barren roof around him.


Fine, he’ll take matters into his own hands.


Yuno watches Asta struggle to keep the guy at bay, the flames sprouting from his sword burning Asta’s skin relentlessly.


“Now repent!”


The exorcist raises his blade and prepares to bring it down on the spirit, but before he can Yuno is between them, arms spread wide as he shields Asta from the blow.


The blade stops less than an inch from his face, the heat of the flames tickling his skin for a second before it’s pulled away.


“W-What are you doing?! I could’ve killed you!”


“I’m putting an end to this nonsense! Asta isn’t evil, and I’m not under some sort of spell!” Yuno says, looking down.


The guy swallows and steps back, looking sheepish. “Look this guy isn’t what you think, if he didn’t murder someone then he certainly did something worse!”


Yuno opens his mouth to counter, but then he feels an arm snake around his waist. Asta’s sword is then at the guy’s neck, and when Yuno turns to his friend the other is glaring with burning intensity.


“I’m sorry you had to find that out Yuno. I had hoped you’d never get to know this side of me.” Asta says, tightening the grip he has on his waist.


“Asta?” Yuno looks down at him.


“I’m sorry mister exorcist, but I still have something to do here.” Asta keeps going, his sword still to the other’s neck, “I can’t let you kill me yet.”


Yuno blinks and then Asta is no longer behind him, instead standing upon the railing again and smiling at them both.


“But when I’m done I’ll be waiting for you to come and set me free.”


Asta’s grin is too radiant for someone who’s just asked someone else to kill them. It makes Yuno so incredibly sad. He wants to help Asta, wants to know more about it. But can someone like him really do anything?




The next day comes by as quick as Yuno expects it to, which is slow and torturous. After their encounter with the exorcist Leopold Vermillion Asta had told him their cleaning session was over. Thankfully the newcomer hadn’t tried attacking the spirit again, vowing to instead keep an eye on him because he seems “worthy”.


Yuno can’t say he quite understands, because those two seem far too eccentric for him to even try to, but he’s still glad that Leo and Asta won’t be fighting to the death anytime soon. It doesn’t stop him from worrying however, because Asta’s words from yesterday still haunt him.


‘I can’t let you kill me yet. But when I’m done I’ll be waiting for you to come and set me free!’


And the bright smile he’d given them only worsened the pit in his stomach. Asta was hiding something, and perhaps it wasn’t his place to pry, but he could tell the spirit was getting himself into something way over his head.




Yuno’s internal monologue is interrupted as a familiar voice calls to him. He turns and waves at Mimosa as she approaches, who takes her seat in front of him. He’s glad she seems fine, since this part of the day is the most normal part of his life now.


“Good morning.” He greets, neutral as ever.


“Good morning!” Mimosa smiles, “Oh my Yuno, is everything alright?”


Yuno raises a brow, “Yeah, why?”


“Well no offense...” Mimosa chuckles, “But you look terrible.”


Yuno does take a little offense, but instead of grumbling he simply reaches up to try and tame his wild hair. He smooths down his clothes afterwards, hoping the bags under his eyes aren’t as bad as he thinks.


“That’s better!” Mimosa giggles, “It’s not like you to look so put off, did something happen?”


Yes. So so much has happened, but he can’t really tell her now can he? Between the ghost’s and exorcist and even those “fairies” he helped Asta catch last week he feels like he can’t catch a break.


“Not really, things are just rough back at the orphanage.” He rests his chin on his palm, looking out the window.


It’s a believable lie, since he’s the oldest kid at the orphanage then he always helps Sister Lily and Father Orsi with the chores and the children. It is tiring, but not overly so, though Mimosa doesn’t need to know that.


“You’re such a nice person Yuno, I would’ve never thought you so caring with children when I first met you you know?” Mimosa says honestly. Too honestly.


“Yeah, I get that a lot.”


“Oh but don’t let it get to you! People will change their minds when they get to know you!”




“Anyways!” Mimosa is trying to save his mood, “Have you heard the rumors?”


Yuno resists the urge to roll his eyes, “More of those ghost stories?” He really doesn’t want to know, because last time he heard a rumor it ended up being true.


“Yes! It’s about the stairs near the art room!” Mimosa ignores his obvious discomfort. “They say if you set foot on the fourth step you’ll disappear!”


“Fake. If that were true half the school would be gone.” Yuno is quick to say, but he’s nervous.


“True, but rumors also say you forget about the people who go missing. What if many people have gone missing and we just don’t remember?”


Now that’s a terrifying thought. To think perhaps people, maybe even friends of his, could have disappeared without a trace, but no one would care because the memory of their existence had been taken with them. Maybe he’ll talk to Asta about it later.


“You really need to stop gossiping about those things, I know for a fact those stories scare you.” Yuno scolds, watching Mimosa sputter.


“H-How did you know?” She asks, blushing.


Yuno rolls his eyes, “You really think I didn’t notice? The last time you told me about a scary story you heard you texted me in the middle of the night because you were “pondering it”. That obviously means you were too scared to sleep.”


“You’re so mean Yuno! At least pretend to be fooled!”


“Not a chance.” Yuno smirks.


That’s when the bell rings, Mimosa turns around in her seat with a pout, both of them waiting for their Professor to arrive so they can start the day. Just as their lesson begins however Yuno notices Mimosa glancing back at him every now and then, as if there’s something she wants to tell him.


When she realizes he’s caught on she stares forward, and he takes it as a sign that she won’t be telling him anything anytime soon. So he let’s it go, trying to ignore the feeling of weariness that coils in his gut.