Rin Takahashi POV:

I opened my eyes and looked around. I was standing in a dark hall as a cold air breezed past. My body tickled for a moment and then suddenly stopped. Where am I? I know that this is the common isekai scenario since my friend Haruko really likes it. I wonder where Haruko is. My one and only real friend throughout junior high and high school. He's probably celebrating the arrival...or maybe he was tricked by a demon, just kidding. I resolved myself and walked down the hall. After a couple of minutes of walking on the cold hard stone, I saw some better lighting up ahead. Without caution, I entered. It was a small office with books and various monster materials sprawled on the shelves and desks. Two people were inside. One was the head desk doing paperwork and the other reading absentmindedly. These weren't normal people though.

The one at the desk had a sort of majestic vibe around him. He donned two black twisted horns on his head and white hair. His big build was covered with muscles and his face would probably scare away children. Especially those blood-red eyes that looked as if eyeing prey. He wore casual attire despite the imposing appearance. The second one who was reading was so skinny it looked like he could fall over with a single push. He wore circular glasses and more formal attire. I couldn't read the book title of what he was reading in another world, as expected. 

"Hm? Who're you?" (said in Demon Tongue the common language of the demons)

It seems I don't get time to think about it. I didn't even know what he was saying. After showing a confused expression...

"A human? Assassin? No, why would an assassin show themself at the front door? You don't look like an assassin either." (both demons switch over to Human Tongue)

"My Lord, I believe this is the one that triggered the magic alarms. The ones the guards are searching for right now."

"Hoho, you must really be stupid for coming straight into the heart of the Demon Lord's castle unarmed and vulnerable."

"Um, excuse me?"

"What does this lowly human want to say?"

"I'm lost."

"..."

"Where are you from?"

"Japan."

"Japan? I think I've read about it before...oh yes! I remember it's the country that the summoned heroes always claim to be from!"

"So you're claiming to be a hero lass?"

"I don't know if I'm particularly a hero..."

"It seems that she's not a hero, just a person from another world."

"How do you know that?"

"[Appraisal]."

"So if she's not a hero, then why is she here? Didn't they just perform the summoning ritual?"

"Yes, my sister Shidora lead those competent in spacetime magic to interfere in the summoning. They managed to send 12 of the supposed heroes to random locations and return back safely."

"So one of them washed up directly here huh? That's how she got past the traps and barriers. The alarm was tripped anyway though."

"My Lord, what shall we do with her."

"It doesn't look like she knows anything. That means she shouldn't have any preconceived notions about us."

"My Lord!?"

"Look here lass, my name is Dakias Eron. 127th Demon Lord, Dakias Eron. I'm fighting a war against the Human Kingdom of Astean who worships the Goddess of the Stars Astria. We were winning the war, and so Astean used their trump card, the Hero Summoning. This would summon heroes of another world to face off against the demon armies and win the war. We interfered with that Hero Summoning to prevent that and you ended up here. There should've been 30 people with you. 11 of them were sent to random locations and 18 managed to safely land in the throne room of the Astean Kingdom's Palace which is located in the capital city. You got stuck here in the heart of the enemy territory. Now knowing that you are an existence summoned for the sake of killing me, what will you do?"

I was put on the spot and my social anxiety kicked in. I mustered up my courage so that I could keep my life.

"I would not agree to kill you unless I knew what kind of person you are and what you did first."

"Hm...well, I'll tell you what I'm fighting for then. I'm fighting for the equality and better treatment of demonkind. Humans, particularly those of the Astean Kingdom advocate human supremacy. They even exert this attitude towards beastkin. We've been constantly killed and harassed by humans that truly believe they're in the right to oppress us. I hate those humans and I hate the goddess that allows such vileness. It's too frustrating. So, as the Demon Lord, the one that unifies demons, I decided to push back. Considering our abilities, force size, and geography, the war was supposed to run smoothly. However, humans are resilient creatures. They come back after growing stronger when you leave them behind on the battlefield. They fought back vigorously and thousands of each kind have died. What do you think?"

"It may be true that the humans were in the wrong for their deplorable behavior, but a war as bloody as this..."

"True, but humans have kept this behavior up for centuries. It is a problem that has plagued even the demon lords of old."

"I think you should really come to agreements with the humans instead of forcing your way to destroy the system."

"Hoh, you think very positively of those humans. Are they not of a different world to you?"

"They are still humans. I haven't met any in this world but I think they're probably the same. But, war isn't the answer."

"Well, it's too late. Too many resources have been expended at the cost of this war. We might as well finish it and fulfill the cause."

I was getting worked up. I never thought of the day where I would get worked up for anything other than anime and manga. Seeing the world of Earth overcome war and reach more peaceful times gave me the upper hand in knowledge here. I know what a war like this will lead to.

"The humans are in the wrong, but so are the demons. Those ideals are wonderful but they were carried out wrong."

"That's it! I'm no longer standing for a lowly human like you to insult my Lord's great decisions. You don't understand how the demon race feels. This is it...a mere human like you would never be allowed in this place anyway!"

"Shidoru!?"

"Burn to ashes and lament your actions, [Laser Ray]."

Shidoru, Dakias's right-hand man, with formal clothes and glasses, fired his famed [Laser Ray]. [Laser Ray] is a magic skill that compacts mana and shoots it in a beam while giving it the fire attribute. It can pierce many things with its high energy density and explode on impact as well. Shidoru is known for using this skill through his eyes. Despite being physically inept, Shidoru is a perfectly skilled demon that specializes in attack magic. He's also good at military strategy and economic management, earning him the position of Demon Lord's right-hand man. Such a move that would reduce most humans to dust was completely blocked by me though.

"[Barrier]."

"..."

The [Laser Ray] was deflected and landed in the room's corner. A fire was going to start but Dakias whiffed it out instantly using [Wind Magic]. 

That was close. I checked my [Status] and I actually had a useful ability. If I didn't use that I would've died.

"I saw that skill when using [Appraisal], however, to think it could deflect a high level [Laser Ray] so easily..."

Shidoru was conflicted. Dakias was also deep in thought. He began to speak.

"Rin Takahashi. You have two options. Enter my army, or die by my hands."

The choice was obvious. I didn't want to end my life at 16. I could also try and make peace with the humans from the inside. I might even reunite with my classmates...not that I particularly wanted to. The only one I would miss seeing would be Haruko.

"My Lord, this is unprecedented!"

"It's fine. She can't do much damage if all she can do is make barriers. The quality of it as well. That can strengthen the castle's defenses don't you think?"

"Are you seriously allowing a human, no a summoned person from another world meant to kill you, into the army?"

"Yes. Even if she isn't useful, she could be used as a hostage for the other heroes. Wouldn't it also be interesting to see their faces if they realize that they're fighting someone who was summoned along with them?"

"My Lord, you may talk about equality and protecting demonkind but..."

"But?"

"But you truly have bad hobbies."

"You think? Well, what do you say Rin?"

"I don't really have a choice, do I? I doubt I could take on a Demon Lord."

"Then it's decided. I'll get you a room and some human food to boot. We should begin thinking about how to use that power of yours. We should also begin training you as well."

"Training?"

"Yes, just the basics. Swordsmanship and magic. How could you call yourself a part of my army when you don't know a single thing about either of those?"

"My Lord!?"

"It'll be fine. Now, Rin, off you go."

The guards were stationed at the front door waiting for the conversation to end. They got ready to escort me to the room Dakias assigned. The expressions on their faces looked as if they suffered a crushing pain in all joints. They just witnessed a human join the army. One of the humans they absolutely hated and were fighting against was given preferential treatment by the Demon Lord. Dakias sure is a reckless ruler. I walked into the large room and jumped onto the bed. Even now, I'm being watched by demon guards. How did my life end up like this I wonder? I have to fight for the Demon Lord after being summoned. Sure, I won't see my family again, but I also can't indulge myself in the Japanese culture anymore. This sucks. At least reward me for trying my best while talking today...I miss Haruko.

[Demon Lord's Army Trainee] - A trainee for Dakias Eron's demon army. The training can vary depending on the focused position. Training becomes a bit easier as an effect.

[Barrier] - Create an impregnable barrier that can't be easily broken. The shape and effectiveness can be changed by the owner's will. The barriers also have the ability to somewhat naturally deflect/reflect supernatural attacks.

[Traitor] - Title given to one who has betrayed. No effect.