Miasma

Disclaimer: I own neither High School DxD nor Demon Slayer. This story is purely fan fiction. Please support the official release.

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●Muichiro's POV●

The moon glows softly as it looms over the land, casting a soothing blanket of light over my surroundings.

It would have been the perfect time to enjoy some sake or tea if it weren't for the fact that I am currently on the prowl.

The rooftops turn to a blur as I run and jump across them.

Slowly but surely, I can feel my physique improving. My training is proving to be effective, and my body's foundations are becoming solidifying. Not as fast as I had hoped, but progress is progress no matter how little.

Not only that...

"Water Breathing, First Form: Water Surface Slash."

My limbs becoming more fluid, I make a great leap, my target none the wiser until its decapitation. The stray devil's head slowly slides off its neck and drops to the dirt.

Good, my control seems to have improved as much as my strength.

Finally, a little more than a month after returning from death, I have begun touching up on my other breathing techniques.

The result was this.

Water Breathing is the easiest to learn among my techniques since it doesn't require much when it comes to the user's strength, and capitalizes more on their flexibility.

So it isn't that surprising that I found myself re-training this one first, given how my current body is still weak, very similar to how I was during my prepubescent years back then. It is actually the very first Breathing Technique I created during my past life.

Leaving aside my improvements though.

It's been a week since I started training Issei.

While not as impressive as Koneko-chan's, the speed at which he improves was nonetheless worthy of praise.

Just a week ago, he couldn't even go beyond 10 minutes running with four logs on his back.

Now, he could match Koneko-chan with eight logs, but only for about 40 minutes.

A huge leap compared to how he was last week. To the point that Koneko-chan grumbles from time to time in indignance.

Good. The friendly rivalry between them will lead to faster growth. Although it seems Koneko-chan is the only one aware of such a thing.

I sometimes find her sneaking a glance at him from time to time. Mostly out of frustration, but there are times when I see something more in her gaze.

I wonder what it is...

Moving on.

As expected, he is diligent when it comes to training, even if he complains profusely.

At the rate he is going, he will be able to square up against that Raynare bitch and her lackeys sooner than I thought.

Come to think of it, I haven't seen them since then...

It's odd. I expected them to at least pop up somewhere in the past two weeks, but they have been completely inactive since that night, almost unnervingly so.

Could I have scared them off? Or perhaps as time passed, their mission proved too risky in the presence of Rias Gremory and Sona Sitri?

The former seems possible but unlikely, I am certain that by now whoever's behind Raynare and her group has been informed about me. Only my appearance though. I didn't tell the bitch or her lackeys my name.

Here's hoping they don't somehow find out through other sources. I heard from Grayfia-san how her master is well acquainted with the leader of the Grigori, after all.

I am not very familiar with the average power level among supernatural beings in the current era, but assuming that Grayfia-san stands at the middle ground, I should be right about there in terms of my current strength at the moment.

...

I think?

Based on that, it is safe to assume that Raynare is a low-ranking member in her organization's hierarchy, meaning that defeating her isn't enough to dissuade her higher-ups from taking further action.

Reinforcements are inbound. It isn't a matter of if, but when.

About the two devil heiresses, though...

What in Yomi are they doing? Seriously, hostile forces have entered their domain, you know?

Aren't they supposed to, I don't know, take action?

A smidge of anger blooms within as I remember how Issei nearly died.

An innocent human would have died under their watch had I not interfered. Solid proof of their incompetence.

...Maybe that's unreasonable of me to expect from them. Rather than them, aren't the better targets for my anger the idiots who thought it reasonable to give them near-complete control of this town?

Just how did it come about that they were put in charge of this place as its overseers?

They're still children, for Amaterasu's sake...

Come to think of it, it is all but confirmed that my employer is Rias Gremory's older brother, and negatively overprotective of her.

Judging by how he must be an influential figure in the Underworld, what's not to say that he pulled some strings to have her instated in her position of power?

Furthermore, there's the possibility that Sona Sitri's case is in any way similar to her fellow King.

...

Holy shit. That is one odd rabbit hole. Better to just ask them in person instead of wasting my brain cells.

My breath turns to mist as I let out a heavy, exasperated sigh.

Aside from that one stray devil a while ago, I haven't come across any other monsters going bump tonight.

Perhaps I've killed them all by now if I've counted the 209 corpses correctly.

How did I dispose of them, you might ask?

Simple. I didn't.

That job is pushed onto those two Heiresses. It's the least they could do in the face of their other shortcomings.

Suddenly, the stench of blood hits me.

Turning my head, my eyes land on a particularly dark alley.

This can only end well...

One after the other, my feet carry me in the direction of whatever's waiting for me in the darkness.

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As I thought, rather, as I feared.

My breaths quicken slightly at the sight in front of me.

Blood. Everywhere.

A cold, lifeless corpse lies sprawled against the wall. A female, but that is all I am able to tell from it.

I can't even make out the expression on her face because of the thick layer of blood.

Long, black hair, curly at the tips.

Just like mother...

No. Don't.

I steady myself, taking in and letting out a deep breath.

Focus on investigating...

No signs of a struggle. Tensing my eyes, I look deeper and see that she does not possess the necessary muscle composition to put up any kind of fight.

I ignore the blood and dirt that stain my knee and kneel.

Poor girl...

She died a very slow death.

Exactly forty stab wounds. All are made with different blades.

30 small ones peppering all four limbs, done just to inflict excruciating pain. Probably a knife.

10 fairly deep ones, all located near vital organs. A sword. They are somewhat cauterized, meaning it is either no ordinary sword or the sick fuck went out of his way to heat the blade.

Various other injuries including slashed tendons at her ligaments, severe burns, shattered bones, peeled skin, missing teeth...

Bastard...

Veins bulge on my arms, my nails digging into my palms.

Whoever did this, wanted her to suffer. They made sure she suffered pain unfathomable.

I do not consider myself a hero, far from it, I spent my past life selfishly chasing, thirsting for revenge.

But...

It seems I cannot help but react as I have when such a brutal, tragic scene is thrust in front of my eyes.

Still kneeling, I part her bangs to find her features contorted in agony. Her eyes show a lifeless blue-gray. They must have shone a beautiful shade like the sky in life.

Closing them with my left hand, I raise my right and close my eyes in a short, silent prayer.

"Cargoless,

Bound heavenward,

Ship of the moon.

Here I pray,

That you may rest in peace,

Relieved of your pain,

That your body,

Might be dew in a field."

Slowly opening them back up, I cast my gaze upon her bloody figure. Boiling anger in my chest.

"And I vow, I will find whoever did this to you."

Pressing both palms together, the fabric of my sleeves stretch as muscles bulge from my rage.

"And they will suffer."

Oh, how easy it would be to just smash through all these buildings until I find this motherfucker...

No. Not like that. Save your anger for when you find him, imbecile.

I must have stopped breathing at some point. The alley is dry, yet steam comes out as I exhale a deep breath.

"The blood is not warm anymore, but it hasn't clotted at all either. Not too long ago, huh?"

Turning to look back in the direction I came, I see two sets of footprints going in my direction. One matches the soles of this woman's shoes while the other is bigger, probably belonging to a man.

No prints could be seen going back out, suggesting...

Swiveling my head, I find one set of prints starting from here and going deeper into the alley. I could smell more blood that way too.

Good. He hasn't gone too far.

I dash through the darkness, small beams of light slipping through the gaps between the buildings.

The scent of blood, a string tugging me in the right direction.

Slowly, the walls and ground start deteriorating, showing signs of decay and neglect.

I must be in the bad part of town.

The sight of my destination further reinforces this thought.

Exiting the alleyway, I come upon a mundane house, much like all the others around it. The only difference would be the thick scent of blood and viscera. Tensing my eyes, a picture is painted of its insides.

No presence is detected on the first and second floors, yet when I switch to my nose, I am bombarded with what I can only describe as miasma.

Rotting flesh. Smells so foul I am nearly forced to cover my nose lest my eyes water.

This motherfucker, looks like that woman isn't the first time he's done this.

The palpable aura of death and wails of agony almost seem too real.

Unimaginable horrors await and uncertainty rises within me, but before I knew it, my feet had already carried me to the front door and my hand had reached for the knob.

Locked, huh?

I pull out some hair pins and get to work at once.

What? With hair like mine, isn't it only natural that I have these on hand? One of the more convenient and cost-effective inventions among others.

Focusing my eyes once more, the inner workings of the doorknob are revealed as I get to work.

The devil-net is such a convenient thing. A random person like me can find all sorts of information that I can use for the most heinous of crimes. However, it is also lucky that this lock in particular is the most common kind found in most Japanese households.

Wait, does this count as a crime? I mean, I am breaking and entering, but at the same time, I have reasonable suspicion that the monster beneath this house has committed horrible atrocities, crimes punishable by law if I were to be proper about it.

Come to think of it, don't I also need to be a registered law enforcer for that notion to be applicable?

Hmm, maybe-

Before I know it, I hear a small click. My thoughts come to an abrupt halt.

Ever so slowly, I open it.

An extremely dreary interior greets me as I enter and silently traverse the very much abandoned home. Perhaps it housed people at some point in time, but all I find now is naught but clouds of dust in the rooms on both floors.

Meaning that...

Making my way back downstairs, my nose picks back up on that foul smell as my eyes point me to the brick wall under the staircase.

It looks like any of the other unassuming walls around the house, but I can hear it.

An air current. There's something behind this wall.

Please be a secret door, please be a secret door, please be a secret door....

I pat around it several times until one stone in particular sinks in slightly.

A secret door. Yay...

The air turns ominous as slowly, a section of the wall big enough to fit a person sinks in, giving me a look at what is inside.

Stairs, of course.

I can only see the first few steps going down. The rest are shrouded in darkness.

"Well, here goes nothing..."

Into the belly of the beast, I go.

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A/N: Sorry, it seems the time has come for my upload schedule to become erratic.

College things.

Thanks for reading! Tell me what you think in the comments!