DxD : The Siscon Demon King and the Swapped Princess

Powers like the Siscon Demon Lord and Switch Princess? From what I remember, stray demons are usually treated as cannon fodder in both the original work and fanfiction—used to test the protagonist's strength, show off their power, or save some heroine under attack. In reality, they pose no real threat in this world.

In the world of "High School D×D," there are countless monsters far stronger than them. My confidence is starting to waver.

There are powerful stray demons, but they're original characters from the source material who were also popular in fanfiction. She's an SS-rank powerhouse who can wield mystical "senjutsu" abilities, and she's also a stunning beauty with cat ears and a tail. I thought to myself, "It's not like adding more S's automatically makes you stronger," but I'll ignore that for now.

All I knew from the original work was that she was formidable. But this much I understand—she operates on a completely different level compared to the stray demon I encountered. That creature was probably nothing more than a minor nuisance to the true powerhouses lurking in this world's shadows. Even to someone like me, who only possesses a sacred gear, or to ordinary humans, it must have seemed like the grim reaper itself.

"Stray demons, devil reincarnation, the three great factions..."

"I can't go into too much detail, but that's what dragged Kei-san into this mess. Normally, the three great factions maintain surveillance to prevent ordinary people from getting entangled in the supernatural world, but sometimes criminals or predators slip through their net. Unfortunately, there are also people from the surface world who become their targets."

"...Are you part of the Three Great Factions?"

"I don't belong to any faction. I'm just an ordinary person with a sacred gear. I know a lot about this world, but that's the extent of it. As for the sacred gear—it's a tool created by God with mysterious powers, as I mentioned before."

"An ordinary person... Then why did you help me?"

"I didn't do anything worth boasting about saving you. The reason Kei-san is alive is because you refused to give up and kept fighting. I just couldn't bear to abandon you, so I desperately tried to do something, anything."

I told her everything I knew about this world's hidden side. No matter what we decide to do next, we can't move forward in complete ignorance. When I arrived at her house, Kei-san was relatively calm and listened quietly to everything I had to say.

This was for her benefit, but it also felt like I'd finally released some of the weight that had been building inside me since my reincarnation. For the past four years, I couldn't talk to anyone about the hidden world. She was a victim, but we could share our fear of this world together. Even if we just kept saying "It's terrifying, it's terrifying," having someone who understood made me feel incredibly relieved. I really am pathetic...

"No, even so, if you hadn't been there, I would have been killed by that monster. So thank you for saving me. Thank you so much..."

"...You're welcome. I should be thanking you for not giving up on life."

"Haha, what kind of thank you is that?"

When I offered those words of gratitude, Kei-san blinked in surprise for a moment, then smiled mischievously. The wounds on her body and mind were still deep, but seeing her smile like that filled my heart with relief. I may be pathetic, but I'm glad I didn't give up. I'm glad she's alive. I truly felt that way.

"Hey, do you think that stray demon is dead?"

"I didn't see it with my own eyes, so I can't say for certain, but I'm confident it's finished. The main reason I did something so conspicuous was to draw the people behind the scenes to that location. Those in power wouldn't just ignore an incident that can't be handled through normal channels. Even if the stray demon somehow survived the crane attack or managed to escape, the commotion would inevitably alert the relevant parties. Professional demon hunters will gather to track it down. It's only a matter of time before it's eliminated, or at least loses the ability to approach this city."

"I see... What do you think those behind the scenes will do now?"

"Right now, they're probably busy with damage control, but once things settle down, I think they'll start investigating what happened. However, I used my sacred gear's power to obscure the scene, and I employed techniques to mask our presence when we escaped, so there shouldn't be any evidence we were there. I believe the warehouse was completely destroyed."

I was about to add "probably" at the end, but decided it was better to sound confident rather than create more anxiety. I don't think the original work covers this particular area. There might be magic, tools, or even sacred gears that could be used for crime scene investigation, but by then it'll be too late. I haven't read the original work cover to cover, so I can't say for certain—which is frustrating. Still, there was no other choice.

Actually, she's in worse shape than me. She was with the two missing victims, and there might be witnesses who saw all three of them together. In that case, she'd have no choice but to claim she escaped by chance, but I don't know if she can pull that off. She's lost so much in this incident, and her wounds haven't healed yet.

"...What should we do?"

"If you want to continue living in the normal world, I think you should keep everything about the supernatural world secret and live as you normally would. Especially now, when everyone involved has gathered in this town. But if you have the courage to live while being involved in the supernatural world, revealing that you're a victim could be an option. If you're lucky, church officials might protect you, or they might teach you how to heal the emotional trauma you've suffered. As a sacred gear wielder, if my identity is revealed, I probably won't be able to return to the surface world. But I think they'd let you go back if you were just caught up in everything."

If that happens, just keep my involvement secret and say you were saved by chance. I'm honestly anxious, but I have no choice but to trust Kei-san.

Besides, I don't think she can live a normal life on the surface as she is now. Even now, the dark circles under her eyes are severe, and she looks exhausted. She told me she occasionally hears the laughter of that stray demon, like auditory hallucinations, and can't bear to be alone in a room. It wasn't until she held my hand—the hand of someone whose true nature she doesn't even know—for a long time that her body finally stopped trembling. I've decided to help her survive.

I believe that's the responsibility of someone who saved her. Above all, I want her to live. That means it's not good for her to remain in this state. But I don't know how to heal Kei-san's trauma.

Even if she goes to the hospital for examination or sees a psychiatrist for counseling, I don't think her symptoms will ever completely disappear. She can't tell people on the surface about what happened in the supernatural world. The wounds she's suffered will remain with her for the rest of her life.

"Kei-san, what do you want to do?"

"What do I want?"

"I have a sacred gear, so I'm already halfway into the supernatural world. But you can choose to live in the normal world as you are, or you can choose to enter the supernatural world. That's why I'm asking."

"Of course I want to live the same way I always have... I don't want to go through that again... I don't want anything to do with demons, the Three Great Factions, or the supernatural world!"

"Kei-san—"

"But, but! I can't just go back to living like I did before, knowing nothing! Even now, his laughter and everyone's screams won't leave my ears. I hear voices asking why I'm the only one still alive... I'm afraid of sleeping, afraid of the darkness... I want to live, but I feel like I have to live for all of us. Even though I understand that, I can't bear to keep living like this forever..."

The tears that broke through, the emotions that overflowed—this was her heart's cry. Kei-san's wish was to live in the normal world, without getting involved in the supernatural. But to live in the normal world, her wounds were too deep, and without treatment from the supernatural side, they would likely never heal completely. There was also the option of receiving treatment from the supernatural world and then returning to normal life, but it was uncertain whether her mind could withstand that process. She was currently clinging to life by a thread.

Being dragged into the hidden world is something that, for ordinary people, would be dismissed as simply bad luck—it's that rare. At least, someone like Kei-san, who isn't a sacred gear wielder like me, might have been able to live her entire life without getting involved. If only she hadn't experienced that trauma.

"I want to go back. Back to when the three of us could laugh together, when we didn't know anything... I want to go back."

"There are sacred gears that can stop time, but none can reverse it."

"Then I want to forget... It's painful that those two aren't here anymore, but I'd rather preserve the happy memories as they were than have them overwritten by bloody ones. I want to forget everything, right now."

"...I do have the power to manipulate memories, but it requires cooperation from those involved on the supernatural side. So if I were to erase Kei-san's memories, that would be the only option..."

—Erase memories?

"...Hey, partner?"

It was just a small whisper to call out to the other presence. But my sacred gear clearly understood the intent behind it. As the thoughts flowed through, I smiled faintly. At the same time, tears welled up in my eyes. Feelings of relief and sadness overflowed within me.

So there's still something I can do, even someone like me.

"Kei-san, if you could really erase your memories, what would you do?"

"Huh?"

"Yesterday, that day, that moment. Stepping into the warehouse, meeting that stray demon, the truth behind your friends' deaths and their screams, the moment you almost died, the despair you're feeling right now... If you could erase all of that, what would you do?"

"Really? Can you erase it?"

She continued crying in shock, and I nodded firmly. I thought I had finally found someone who shared the same burden, but there was nothing more I could do. Above all, I'd come to believe this was the best outcome.

"I did explain the effect of my sacred gear, right? This spear can inflict the power of annihilation on its target. You can also choose what that power targets, and in my case, the effect activates simply by wielding it."

"...Yeah."

"This annihilation has two effects. By selecting a target, you can temporarily erase it, and the other effect completely obliterates the target instantly, leaving no trace. I mainly use the former. However, to use the temporary erasure on others, you have to keep stabbing them with the spear continuously, so I don't recommend it. But the latter effect, which is the original intended use, allows you to activate it by selecting a target and stabbing once."

"Does that mean you can target memories for erasure too?"

"I've erased conceptual things before. Memories are quite delicate, so it takes time and stamina, but... it seems possible."

"—!"

Of course, I've never tried this before, so it'll be a shot in the dark. More than anything, I've only ever tested the sacred gear on inanimate objects. In other words, this will be the first time I've used it on a living being—a human being, no less.

I made sure to explain the risks clearly, but I could already see the answer in her eyes. Part of me wanted her to refuse, but I pushed aside my cowardice and summoned the sacred gear with resolve.

A single crimson spear appeared in my hands. My precious partner, always has been and always will be.

"To erase the memory, I must stab Kei-san with this spear. It will hurt. Blood will flow. Moreover, memories are delicate, so erasing only the problematic parts may take time even after the initial stab. I'll say it again—it will definitely hurt. There are safer ways to erase memories, but those involve getting the supernatural world involved. Even so, do you still want to erase those memories here and now?"

You can think about it more later. It's only been a day since yesterday, and you're probably still in shock. You've received treatment, but your injuries haven't healed yet, and your physical strength is low. Maybe it would be better to wait until your physical wounds have healed. If we give it some time, we might be able to contact the supernatural side and erase the memories more safely.

Kei-san silently shook her head in response to all my concerns.

"...Will Akiko and Yuri be angry with me? For forgetting their deaths, their final moments, and trying to live on with a smile?"

"They'll only be angry if you give up on living. And I'll be angry too. We survived that day because we both fought hard. So please—live your life with a smile."

"Yeah... yeah..."

"If you erase your memories, I think you'll be confused afterward. You'll experience the pain of losing your friends all over again in a different way. Also, I'll take care of you after the memory erasure, so please don't worry."

"I'm really sorry. I'm not just erasing the memories of the demon and those two, but also the memories of you. You saved my life and helped me so much."

"Don't worry about me. But promise me this—you must live until the very end. And please keep smiling. Even if the memories are erased, please don't forget the determination and feelings that refused to let you lose to that monster."

"...Thank you. Thank you so much."

The first person I could finally confide in about what I'd been hiding. The first person I could save from death. The first person I truly wished would live happily. The first person I would stab with my sacred gear. And the person I would never see again.

"Hey, can you tell me your name before we part? Just for a little while, I want to know you properly. Please."

"...My name is Sota. I'm in eleventh grade."

"Haha. I'm a second-year university student, almost twenty."

"Wow, so you'll be able to drink soon."

"Yeah. Oh, but you shouldn't drink, Sota-kun. You can't drink until you're twenty."

"I know that without you lecturing me like a teacher..."

"Ahaha."

Kei-san's smiling face looked younger than her age and was incredibly beautiful. It was only now that I realized how stunning she was. Her light brown hair suited her perfectly, and she had a wonderful figure. If I were the protagonist or main character, I would have already triggered a romance flag.

Instead, I was the one blushing at her smile—maybe that was the real flag. If so, what heartbreak this is. Farewell, first love. Maybe people who wield spears really do have terrible luck stats.

I aimed the spear at her left arm. Her legs would be more important for daily life, and she was right-handed, so that was my target. I tied off her arm with a bandage to minimize bleeding and prepared medical supplies—hot water, towels, gauze, and bandages. I spread a vinyl sheet in the room, had her lie down to conserve her strength, and positioned her left arm higher than her heart.

Everything was ready. All that remained was to stab her with the sacred gear. A shallow stab might fail, so I had to pierce deep enough to penetrate the flesh. I focused on causing her as little pain as possible. As I took my stance, Kei-san closed her eyes tightly and waited for the moment. I closed my eyes once, took a deep breath, and slowly exhaled.

In my previous life, I had never hurt someone like this. I had never held a weapon or cut into flesh. Well, that's only natural—it would be terrifying if I had. Maybe someday in the future, I might have to point a weapon at someone. But in that moment, there won't be time to hesitate or steel my resolve. That's why I can't run away now. I'm going to live my life to the fullest in this world.

"Goodbye, Kei-san."

"Goodbye, Sota-kun. ...Sota-kun, don't give up—live until the very end."

"Of course."

We said goodbye with smiles on our faces. And then I thrust the crimson spear into her.

***

[Power stones and reviews please]

Support link: www.patr eon.com/Well_being

[10 Advanced Chs] [7 Chapters/week]