My brother is a demon || Demon slayer role swap au

° a strange sent °

Nezuko Pov

Maybe it was the sent of the air, or the sound of the birds, but for some reason today I had a terrible feeling something terrible was going to happen. I sighed softly to myself as I climbed the mountain. I had just left my grandfathers house. He wasn't really, but I liked to call him that. I stayed there as it was getting dark after I finished helping the townspeople and selling coal. Tanjirou usually does this but he had gotten ill so I took the job. I should bring Tanjirou and the others to him when Tanjirou gets better, I thought to myself. After a while I froze to the sudden smell of blood, I began to hurry as worry and fear took over my body. When I made it to my house I saw Tanjiro over Rokuta, they were both bloody. I cover my nose as the stench of blood became worse as I looked inside the house. Every where was blood. I began to cry as I saw my mother, she was gutted out completely and her once peaceful face was clouded with fear. I began to check my siblings, looking for a pulse. My eyes filled with hope when I felt that Tanjirou was still warm. "Don't worry Onii-San! I'll bring you to a doctor!" I said with hope in my eyes as I moved quickly. I got Tanjirou on my back and began to run downhill. 

Don't worry Tanjirou! Everything will be okay! I'll make sure of it! I thought as I was running down a narrow path. It was steep and a there was large drop, so I had to be careful not to slip. I began to hear growling and hissing, "UGGGHHH RRAAAAAHHHHH RRRRRRR" I looked behind me and saw Tanjirou awake, but his veins were popping out of his head. He began to struggle in my hold. "T-Tanjirou! No stop!" I yelled as we began to fall. I let out a gasp as I hit the snow. I sat up quickly, glad that the snow was so fluffy and saved my fall. "TANJIROU!" I yelled worriedly, after a moment I got pinned to the ground by Tanjirou. "Tanjirou! Please stop it!" I yell fearfully, I grabbed the hatchet that was on my waist that Tanjirou gave to me just in case.  I got it stuck between his mouth to prevent him from biting me. His teeth sunk into the wood of the hatchet. "T-Tanjirou!" I yelled as I held him back. He began to grow bigger as he pushed down. "Tanjirou! Big brother! Please it's me! It's your little sister! I know your hurting, but please don't hurt me! I want my Onii-san back!" I yelled with tears in my eyes. I looked up as I felt tears fall on my cheek. Tanjirou was crying as he slowly shrunk back. I slowly sat up and hugged Him, he let out quiet sobs as he hugged back. I froze when I heard something swinging. I moved Tanjirou over with me to avoid the swing of the sword. I looked at the attacker and my pink eyes met with an icy blue stare. 

"Why are you protecting it?" He asked as he raised his sword. I growled at the name it, the word made me feel enraged. Tanjirou was trying to escape my hold, letting out loud growls and groans. "He is not an it! He's my brother! H-he and my family got attacked and he's the only one left!" I yelled out. "Are you kidding me? You were just about to get eaten not to long ago." "No I wasn't! He knows who I am! He would never eat a human! I am going to protect him!" I yelled. I thought I saw him roll his eyes as he dashed towards me. I bent over Tanjirou to protect him, but I realized nothing was there, I looked up and saw the man holding my brother as he struggled in his grip. "N-No leave him alone! Don't hurt him." The man looked at me with an emotionless expression. "Your brother is a demon, he was most likely exposed to demon blood from his wound. That's how man eating demons multiply." He said. "Your brother is now one...so I'm going to decapitate your brother." He then stabbed Tanjirou in his shoulder. "NO! Please don't! He's all I have left!" I cried as tears began to flow down my cheeks. 

"Get up!" He yelled "The weak have no rights! They don't get to make choices! All they can do is be relentlessly crushed by the strong! Now maybe the Demons know of a way to cure your sister. Maybe! But don't think for even a moment that any one of them is going to respect your wishes, just like I have no respect for you! That's reality!" He yelled. I looked up at him and stood up slowly with my hatchet in had. "If you want to protect your brother, fight me!" He yelled at me, trying to get me to be confident. I slowly breathe in and out, gripping the hatchet hard. I picked up a rock and threw it at him to distract him, which worked of course. I ran behind some trees and threw the hatchet up in the air before throwing another rock at him. He dodged that one, just like the other one. I ran up to him, pretending to have the hatchet in hand. In rose my hands up like I was going to attack him but soon fell and passed out.

Giyu Pov 

I looked down at the girl who was now passed out. I thought for a moment and looked around. Where's the hatchet? I thought as I looked up and quickly dodged to the side. She threw it and distracted me with that rock. I looked at the demon, who the girl called Tanjirou. He was struggling to get out of my grip. He moved and kicked me in the ribs. He then ran for the girl. He's going to eat her up! I thought as I got ready to save the girl, but instead I was surprised as Tanjirou stood in front of me, protecting her. He growled angrily at me and charged towards me. I quickly hit his neck which cause him to pass out. I let out a sigh as I looked at the two. I took off my Kimono and put it ontop if the two. These two siblings...their different...they have such a great bond that even though ones been turned into a demon, they protect each other... I smile a bit and quickly wrote down a letter to my former teacher mr.Urokodaki. I sent my crow to send the message. I looked around for something to stick into the boys mouth so he will have less of an urge to bite. I saw a bamboo that was large enough to fit in his mouth. I tied a ribbon through it and put it on his mouth.i then waited for the two to wake up.

Nezuko pov

I gasp as I quickly sat up and looked around. I looked down and let out a relived sigh. He's still here, he's alive and well. I look up and see the man from earlier. I grab Tanjirou and hold him close to me. "Keep that muzzle on your brother if you want him to be able to hold back easily." He said as he was leaning on a tree. His cold icy glare felt like it was piercing through me. "You want to be demon slayer?" He asked. I thought for a moment. Would they make me hurt Tanjirou if I became one? What would Tanjirou do? Would he accept? But whoever killed my family needs to pay...they need to pay for what they did. I have to get revenge for my family and kill him before he kills other. I look back at him and nod. "Yes. I want to become a demon slayer so i can kill whoever did this to my family, whoever turned my Onii-Chan into a demon. I will find a way to turn him back." I say with determination. A small but relaxed smile came on his face. "I am Giyu Tomioka, I am the water Hashira with Demon slayer corps. If you want to become one, go to mount Sigri as soon as possible." He said as he began to walk away. "Tomioka-Sama...thank you." I say softly as I hugged my sleeping brother close to me. "There's no need, show me that you are strong." He said as he disappeared as soon as he came. 

I look at Tanjirou and smile at his peaceful face. "Don't worry Onii-Chan, I'll protect you and find a way to turn you human..." I say softly. He leaned into my touch as if saying, thank you, to me.