A Demon's Eternal Vow (Guren x Reader)

Betrayal is Fatal

Your P.O.V

The morning light illuminates the room with unmatchable beauty and the smell of dew dampens the air. I shift and stir, feeling my joints ache in resistance from the commotion of the night before. As I regain full consciousness, I recognize a soft entity draped over my midsection. A blanket curls around my limbs and I ponder how it ended up there. My eyes flutter open and I roll to the left side. Staring down at me are orbs of iridescent violet. "Good morning." He mouths to me and ruffles his hair with his hand. In the soft light of dawn his handsome physique is undeniable. A light pink dusts my cheeks and I fidget in his lap. Upon computing his presence, my blush deepens. It must have been him who took care of me in my deep slumber. He notices my embarrassment and gives me a light smile. He brings his finger to his lips, signaling me to remain quiet. I survey the room and realize everyone is still fast asleep.

A few moments later, Shinoa rises. She sleepily walks over to Kimizuki and shakes him awake. They walk in unison towards the blood analysis machine and remove the paper containing the results. Guren and I gather around, waiting for their response. Shinoa is the first to speak, her tone full of melancholy.

"It seems as though the virus is still persistent in her blood. As well, similar to Yuu, her body composite remains partially demon. Though, this will not affect her health or behavior. The reason she hasn't woken up is due to the rampant sickness raging through her body." The others have gathered around now and a thick cloud of dread looms over the room. "If we cannot cure the virus, she will die." The truth hangs in the air, but no one is able to come up with a plausible solution.

Suddenly, I boast with rejoice. I have mustered up a reasonable idea. The others turn to me in wonder. I stalk over to the kitchen and retrieve a glass. Then, I use my fangs to tear a gash in my wrist. Red blood drips from the wound and I feel Mika stiffen behind me. The blood seeps into the glass until it is half full. I then pass the glass to Kimizuki. I exult with urgency. "A demon's blood will purify her body, removing any trace of the virus. Because she is already part demon, the blood will not harm her. She will not turn into a full demon either." Kimizuki's resolve wavers and he tightens his grip around the cup. Sweat beads his forehead. "This is the only way to save her. I need you to trust me." Kimizuki gives me a confident nod and slowly tilts the cup towards Mirai's mouth. The crimson liquid spills into her throat until nothing remains. Again, we are left to sit and wait. No one will feel rested until Mirai has awoken. From the corner of my eye, I witness Mika pull Guren aside. I watch attentively with curiosity.

Guren's P.O.V

Mika suddenly grabs me by the wrist and pulls me to a vacant corner of the room. I grunt at him out of aggravation, but his worried expression quells my outburst. I sigh and motion for him to continue with his request. "I noticed (f/n)'s eyes." He stops and waits to see if I catch on, but I don't. I just stare at him with confusion and misunderstanding. "Demons and Vampires are anatomically similar. They both need to drink human blood to survive. Once this occurs, their eyes will turn a dark shade of crimson. (f/n)'s have not. This means she hasn't drank human blood." He stops again and I continue to gaze at him unimpressed. He sighs with irritation at my lack of understanding and speaks again. "She is in pain, Guren. If (f/n) was turned into a demon 7 years ago, it means she has gone without human blood for an extremely long time. When I was first turned into a vampire, I refused to drink human blood and each day the searing ache in my throat grew worse. Until it became so agonizing that it felt as if my insides were being torn out through my chest. I was able to nullify the pain for a short while by drinking vampire blood, but no other demons exist in this world. (f/n) not only denied herself human blood, she was also without demon blood. I can't imagine the pain she is in." I look at Mika intently. His speech turns to cries and he grips his stomach. The colour washes from his face and his expression begins to tremble. I feel the seriousness catch in my throat. My gaze darts to (f/n) as she chuckles alongside Yuu. I look for her physique to tremble and waver, but she shows no signs of agony. I open my mouth to ask Mika a question, but the awakening of Kimizuki's sister interrupts me. We all gather around her bedside and waste the day away rejoicing.

Another morning begins like clock work and everyone is gathered in the main living quarters. It is time to discuss our first move to end this war. "Who should we try to win over first?" Mitsuba impatiently questions and everyone turns their heads to me. That's right. I am their commander. (f/n) tugs gently on my sleeve to encourage me. I grin reassuringly at her.

"The human soldiers have been tricked into fighting the Hiiragis' battles. They will not support the General's deceitful and corrupt plans. They just need to see the truth, that's where we will start." I bellow confidently and the others cheer in unison. We spend the next few hours drawing out a detailed plan of attack. Once the route is set in place, we prepare ourselves for our first fight.

Your P.O.V

I lead the assault. Shinya and Guren stalk down the hallway behind me. Frightened faces and stares of disbelief welcome us. These two men have been labeled as traitors, wanted for treason, and now they walk beside a cryptic girl in a black hood. Finally, we approach the door to the General's quarters. I do not knock, I welcome myself inside. The General sits alone at his desk, he is unguarded. He looks up from his work and grunts a sigh of amusement. "What business do you have here?" He growls with violent intimidation. I snicker to myself.

"I am the demon king, Yashirohira and I have come to do business with the mighty General of the Imperial Demon Army." I reply curtly and his eyes widen.

"What kind of business do you propose?" He ponders and I reply rapidly.

"A contract for you to use my power at your will." I grin cunningly and he shoots me a power-crazed stare.

"My boys!" He rejoices and stands from his chair. He marches towards Shinya and Guren, then embraces them in a friendly hug. "Here I thought you had betrayed me, but instead you have brought me a trump card! You have done well!"

"There is one condition." I remark plainly, interrupting his celebration. He turns to me with anticipation. "I want to hear a detailed outline of your plans for this war, so I may know your resolve remains unwavering. If you pass my trial and I deem you worthy, you may use me however you please." I bow and reach out my hand. The general takes it graciously and places a kiss on the top of it. I can feel Guren grit his teeth and I giggle to myself out of mockery. The General returns to his desk and sits down. His stature turns stoic. He speaks with tactical precision.

"I have begun research on the reincarnation of the Seraph of the End. This is a powerful demon I will use to wipe humanity and vampires from the face of this Earth." He hisses and smashes his fist against the table.

"You will not save any of your human comrades?" I rebuke with sinister intent.

"I could care less about those disposable pawns I call soldiers. Humanity is disgraceful and worthless. I have every intention of crushing them under my feet in order to achieve my goals. The only survivors will carry the Hiiragi bloodline. They are the ones worthy of repopulating the Earth. The only thing I care about is solidifying my power and rule over the new world." He belts out and laughs maniacally. Guren and Shinya wash white with disbelief. I snicker and the General snaps his head in my direction.

"Unfortunately your rule ends here." I taunt while holding out my hand. Guren places the recording tape in my outstretched palm and I toss it repeatedly in the air. The General remains frozen in place. His expression contorts from terror to infuriation and he lunges forward. I swiftly toss the tape to Shinya. He exits the room and runs towards the communications booth on the upper west floor of the headquarters. There, Shinoa and Kimizuki wait. "The entire army will soon hear of your betrayal and revolt against you!" I cry out in triumph.

"Return that tape to me or die." He mutters coldly. He reaches for a pin on his uniform and it quickly morphs into a demonic spear.

"(f/n)!" Guren screams and I explode into a torrent of light. The air around me convulses and I transform into a katana. Guren's hands wrap firmly around me and he slicks back his raven locks in preparation to fight. His resolve and fiery passion bound through my body. I have faith in you, Guren.