Satori: This is the entrance?

She asked, her eyes remaining on the closed door leading into the unknown. Koishi, who witnessed the inside of it nodded with her usual smile and pushed the door open, obeying her silent order. The familiar darkness greeted her and welcomed her sister for the first time. Satori stayed vigilant and stepped inside the room, followed by the girl with green hair.

Just like before, the door closed, the lights turned on and the bell began to ring loudly but not enough to damage their eardrums. Used to it, Koishi waited but Satori looked around in confusion, not understanding why a library was hidden so close to Hell.

???: Intruders detected inside the library! Koishi Komeiji and an unknown presence, proceed with caution.

Satori: What was that?

Koishi: The alarm, I guess?

She mumbled back, not sure herself about it. She knew for sure that it wasn't Y/N's voice but as far as she knows, nobody else was inside this place, only him. Wondering about the origin of that mysterious person, she almost forgot that they were here for another reason.

Satori: Where is that human?

Koishi: No need, he greeted me last time.

She responded calmly, holding her hands together in a cutesy attitude that was hiding her lack of real feelings. She was only projecting things she felt in the past onto her face to make others ease up around her.

???: What are you doing here?

A voice asked, making the girl who already visited this place widen her smile. Meanwhile, the new visitor looked in front of her and saw the man with white hair and soulless eyes looking back at them, carrying a sword with him to defend himself.

Satori: Y/N I assume?

Y/N: So she told you about this place, I shouldn't have trusted her, you're both here to finish what you started.

He raised his sword, preparing himself to resume the fight of yesterday. Satori frowned at his behaviour while Koishi looked at the scene with a certain surprise. She thought the situation would go better than this.

Satori: We are not part of the group of people you talk about, we do not even know them.

She calmly answered the statement that he was about to state, such is her ability. Hearing her say that for no reason only raised his guard, knowing that she was acting odd for someone who pretend to not be associated with the ones trying to break inside the library.

Satori: I can understand your suspicion but it isn't the case, it simply is my third eye speaking to me.

She responded back to his thought while showing him the eye around her body, looking at the man in front of her with a dull look, uninterested by the scene. Not understanding what she was talking about, he sighed and leaned against the bookshelf behind him.

Y/N: Not like it would matter, I'll just die anyway.

He whispered to himself, rolling his eyes away from the intruders.

Koishi: Mister Y/N, I returned the books.

Y/N: Hm?

He looked back at her, seeing the book she took along with a second one.

Y/N: Where did you get that second one?

Koishi: I followed you and found it.

Y/N: You're not supposed to bring them back, you won them.

Koishi: ...But that's not what a library is for.

Y/N: *Sigh* Its meaning was lost from the very beginning, it's only a bait for those stupid enough to search for forbidden knowledge.

Satori: Should we assume that everything is inside this place?

Y/N: In terms of books, yes. Anything else? Not much.

Koishi: ...Mister Y/N, you have more syringes than before.

She pointed the army of needles in his back, growing quickly now. Knowing what she was talking about, he took one out and tossed it on the ground.

Y/N: There, better?

Koishi: ...

She shook her head, not smiling anymore. Meanwhile, her sister looked around herself, the numerous paths leading inside this maze. So many books were surrounding her that it made her look insignificant.

Satori's mind: That witch would be ecstatic if she ever saw this place.

She thought that to herself while her sister was arguing with the man about the number of syringes that were in his back last time compared to now. Slipping back into her reality, she looked back at the librarian of this place.

Satori: Say, have you ever been bothered by a certain witch?

Y/N: There's witches too? Give me a break already, this job is the worst.

Satori: So she didn't find this place.

Y/N: Dunno who you're talking about but I can tell that she's a troublemaker.

He responded while taking the books that Koishi was forcing against his cheeks, forcing him to take them back even if he tried to ignore her. Taking them back caused the girl to smile once more. At the same time, he clapped his hands together, causing a book to emerge from the back and float beside him.

Y/N: I guess you're here for that.

Satori: What is-

Y/N: Satori Komeiji, sister of Koishi Komeiji.

Satori: Yes, that would be me.

Y/N: Then this book could be interesting for you.

The book slowly moved closer and she grabbed it, taking a peek at the cover.

'The book of Satori Komeiji, the youkai that sees everything'

Satori: So this is my book.

Y/N: Unless there's a second person with your name, it's yours.

He answered her doubt with a shrug, turning his head to look at the girl waiting by his side with a rather weird look. The both of them were silently observing each other while Satori opened the book and took a look at the first page.

[Satori Komeiji]

[Level: 52]

[HP: 260]

[Stun Resist: 62]

[Passives]

-Sisterly Bond: Constantly recover 4 HP every turn as long as [Koishi Komeiji] is in the same battle.

-Third Eye: The person is capable of visualizing the attacks of the opponent.

-Youkai Instinct: Increase strength by 15% against human enemies.

-Magic: The person is capable of using magic.

-Danmaku Fighter: Increase Evasion/Stun Resist by 20% during battle.

-Flight: The person is capable of flying.

Satori: ...

She looked at what was written there, not sure what to make of it. She knew that it was something close to an appraisal when it comes to her abilities but nothing else past that, it was beyond her. She stepped closer and frowned slightly, seeing her sister talk with the man like they knew each other.

Y/N: I'm telling you that there's the same amount of syringes than before.

Koishi: Hm? I don't think so.

Y/N: What are you going to do about it? Count every single one of them?

Koishi: Of course!

Y/N: ...I was joking.

Satori: Mister Y/N, could you spare some of your time to explain me what you are doing so close to the Underworld?

Y/N: Huh? The Underworld? What's that?

He asked with a genuine confusion. Surprised to see that, Satori raised a single finger in the air like a teacher beginning his lecture. The moment she was ready to begin, the bell above them began to ring once more.

???: Intruders detected inside the library! Unknown entities, proceed with caution.

Satori: Eh?

Y/N: Got some troublemakers.

He looked at the entrance and indeed it was the case. Standing there, an oni was accompanied by 2 fairies lurking inside the dark corridors of the underground, the oni grinning in anticipation.

Oni: So, this is the library they all talk about?

Fairy: Seems boring honestly.

Fairy 2: They did say that we could steal anything if we win.

The strong beast took a glance at the man with his sword prepared and snickered, clearly mocking the human for trying to fight him head-on.

Oni: That's all? A simple human? If that's the only thing here then it won't even be considered an exercise.

They all ignored the presence of the sisters behind them man, all of them knowing that they weren't the target that they had to defeat, maybe they couldn't even see them? That was a possibility since they only kept looking at Y/N.

Y/N: Quite a bother, a brute and 2 pixies, seems like the outside is getting weaker as well.

Satori: What is going on?

Koishi: Intruders I assume? They don't seem to be able to see us.

Y/N: Whatever, I should at least do my introduction.

He cleared his throat and with a ragged look, he gave them an impatient smile.

Y/N: Welcome to the library, the well of knowledge, where everything can be yours. At least, if you can get past your ordeal.

With that, he placed himself in a combat position, making the fairies giggle and the oni crack his knuckles, ready to see a pool of blood in a few minutes. The saddest part would be that they weren't wrong, the odds were all placed against him, fighting an oni alone was suicide.

Satori: Wait, he's going to fight them alone?

Koishi: Huh? He must have a plan.

She hoped it was the case, or else they were about to witness a murder in a few moments. Glancing at each other, they silently nodded and tried to interfere by stepping closer, no reaction from the enemies but a surprised one from the man.

Y/N: This isn't your fight, I'll deal with it.

Satori: And watch you die, not happening, I do not wish to see that.

Koishi: Plus, it would be 3 against 3, it's fair!

Y/N: No need, I simply need to arrange something.

He searched in the black suit that he was wearing and took out a book before opening it. Koishi, the one standing on the side of the cover, looked at what was written on it.

'The book of the dead, the librarians who perished in the library'

Y/N: *Whisper* Please give me your power, Clara, Lulu.

The pages began to glow lightly and afterwards, the book vanished into a small light. Satori didn't notice but she did, leaving her with questions. Y/N looked at the small light with sorrow, a look crippled with horrible memories.

???: Be careful everyone, we can't underestimate our opponent!

Satori: Huh?

She turned around just in time to see a girl jump above her and land perfectly beside Y/N. The girl was wearing a blue uniform and a gray skirt ending around her thighs, the same blue serving as her hair color and a ponytail for her hairstyle. Her eyes were filled with energy and she was carrying the same sword as Y/N.

???: Take a deep breath everyone, I'll protect you if you need it.

A second girl with short blond hair decorated with a black hairband entered the area, wearing a military outfit and carrying with her what seemed to be a dark rifle. The blond girl was wearing glasses and looked more serious than the first one.

Oni: Heh, guess it couldn't be that easy.

???: Y/N, let's show them why we're the best!

Y/N: ...

He nodded silently, holding back tears when seeing the girls standing beside him. The one with glasses silently adjusted them and took aim, the barrel pointed at the head of the giant standing before them.

???: Lulu, in position. I leave it up to you both to take the close combat.

Clara: Will do! Come on Y/N, we won't lose!

With both of them ready to fight, the youkais who were about to help were left silent, curious to see the outcome of this strange duel. While the rifle was ready to kill the oni, Clara prepared her sword and aimed at one of the fairies, leaving Y/N to take the last one. All librarians took their targets and the intruders responded back.

A single gust of wind passed and the fight began.

Lulu: 23, 678, 54.

She pressed the trigger and the powerful sound of the bullet ripping through the air echoed, entering right inside the oni's arm. He laughed at her pitiful attempt and charged at her, ready to crush her with his fists.

Y/N: Hey fatass, over here!

He swung his sword and a gash appeared where he swung, making the large monster turn around to try and punch him. During that time, Lulu took out a pistol out of her outfit and shot him in the back of the head multiple times, dealing the fatal hit.

Y/N: ...Thanks.

Lulu: No time for that, we still have enemies left.

Y/N: ...

He didn't respond, biting his lower lip to suppress the feelings he had right now. Both of them turned to the remaining opponents, shooting projectiles at Clara while she was avoiding them with all her might.

Clara: A little help wouldn't hurt you know!

She yelled at us, slashing an incoming bullet in half with her weapon. Due to the rather small size of the fairies, Lulu tossed the rifle on the ground and took out a combat knife from a pocket, rushing into the fight with a fierce expression. Y/N followed after her and targeted one of them on his own.

Fairy: You're way too fast!

She squealed in fear while saying that, shooting in his direction in the hope of killing him before he could reach her. Used to their magic, he moved aside and continued in her direction, blade ready to be soaked with her blood. His figure approaching her began to cast a shadow on her small body.

With it, the weapon was swung down, tearing a bit of her clothes off along with her skin. The fresh smell of blood began to float in the air but it wasn't enough to kill her. Even if he went all-out for it, his lack of strength was stopping him from working at his fullest.

Of course, fearing the pain, she screamed in agony, a scream that caught the attention of everyone. She was not familiar with the pain, only known for being killed instantly instead of slowly. She tried to cover her wound but it was larger than her palm, burning her when she placed it on her.

Fairy: P-Please, I don't want to die.

Y/N: ...

He swung a second hit and the heart was pierced, ending her suffering. The body fell down and stopped moving forever. Normally, a fairy should not be able to die but now, she was unable to exit the walls of this prison, trapped inside for all eternity along with the librarian who killed her.

Clara: Finally, we won!

She yelled in joy once the second one was taken care of. The last enemy accepted her death the moment she saw her friend being killed by the man standing in front of her corpse, her will to fight reduced to nothingness.

Fairy 2: You're... you're a monster.

Y/N: ...Part of the duty.

He mumbled, stepping away from the deceased fairy. The last one who remained stuttered and tried to reach for the exit, stopped by the sound of a bullet going into the back of her skull, a parting gift coming from Lulu.

Y/N: ...

Clara: Phew, we're done with this.

Lulu: No survivors found, end of reception.

Satori: ...

Koishi: Is something wrong sister?

Satori: Those girls... they don't seem to possess a mind.

Curious, she tried to read their minds but it resulted with complete emptiness, none of them were given a mind on their own, acting on instinct like her own sister. The problem was that they were far from youkais, how is it possible for them to completely suppress their own mind?

Clara: Y/N, we did it!

She jumped on him, trapping him inside a powerful bind that her arms were. He winced in pain and a trail of tears flowed down his face. With his shaking hands, he embraced her back and hid his face in her uniform.

...But it was temporary, Clara and Lulu's body suddenly combusting into pages of a book and vanishing like dust in the wind, leaving Y/N to hug the emptiness in front of him.

Y/N: ...

Satori: Mister Y/N? Do you need to take a moment to breath?

She asked, seeing his teary eyes. He looked down and weakly nodded, sitting down on the ground without saying anything at all. Koishi, not understanding what was going on, approached him and sat down beside him, witnessing the man holding back the tears.

Koishi: Why are you crying?

Y/N: ...

Satori: Koishi, you can't go ask people this sort of thing.

Koishi: Sorry...

She mumbled that out with a quiet voice, only allowing Y/N to hear it properly. The man nodded back but didn't say anything afterwards, keeping the silence inside this library. That silence persisted until his head looked at the sisters beside him.

Y/N: I suppose... you want an explanation.

Satori: If you don't mind.

Y/N: ...It's fine.

He wiped his tears off his eyes and stood up, a more natural expression on his face. Holding onto his sword to support his weak body, he sighed and began to explain what happened in front of them.

Satori: Those people, they weren't alive?

Y/N: ...They were, 'were' being the important part. Unfortunately, they got killed by stronger opponents who entered this library.

Satori: Could you specify?

Y/N: ...Too many opponents caused the death of my friends, I can't remember them all but I surely remember the ones who killed them in masse. One of them if I remember correctly...

He stopped to refresh his memory a bit.

Y/N: Called Suika or something like that. She was a monster who killed 6 of us before we made her retreat.

Satori: S-Suika?

Y/N: Do you know her?

Satori: Not directly but I've heard of her, she's not an oni for nothing.

Y/N: Well, I don't know if we're talking of the same person but she still killed 6 of my friends that day before laughing, saying that we were making too much noise for her taste.

Not wanting to talk about it anymore, he took out he book he used to summon those who died and showed it to them.

Y/N: With this book, I can use it to extract their own past selves. They don't know that they died, only I know the truth and they vanish after a short while.

Satori: You're using magic to bring them back?

Y/N: Yes, although it's a bad one, I'm not one capable of using magic so it's not perfect.

Satori: Even if you can't, reviving people during their own past is something I haven't seen before.

Y/N: There's a reason it's not done... it's painful to do it, to know that you will never see them again.

Koishi: ...So why are you bringing them back?

Y/N: *Sigh* Because I have a goal, a goal that need their assistance.

Satori: ?

She raised an eyebrow, wondering what it was. She tried to peek in his mind to see if she could find his goal but it was filled with memories of the fight that happened a moment ago, forming a large wall.

Y/N: I can't do it on my own, I'm too weak, I'm just a pathetic corpse in this state. That's why I have to rely on them, even if it hurts me to see them like that.

Koishi: What's your goal?

Y/N: ...

He glanced at the book in his hands and frowned.

Y/N: ...I want to bring them back once and for all, I want my friends to have a second chance at life.

Satori: ...

Koishi: ...

Y/N: I'll gladly die for that goal, I don't have much left after all. If my death can make them wake up once more, I'll even bet my life on it, that's the only sacrifice I'm willing to do for this ideal world.