wrong side (Highschool Dxd x Male! kimetsu no yaiba reader)

prologue

3rd person POV

(Y/N) (L/N), demon slayer in training, is currently training with one of his father in the middle of a forest on top of a mountain. currently they are fighting in a clearing with a rock with some rope around it and after a couple hours of fighting they decide to head back to their house which was just outside a small town called kuoh and when they got their they found something that they didn't expect to see, what they saw was zenitsus, inosukes and his step mothers, dead body on the ground with bodies of unknown others scattered around

(Y/N) POV

I couldn't believe what I saw both Zenitsu sensei, Inosuke sensei and Mitsuris dead right in front of me the other bodies must be the attackers, but what is with the black wings?

(Y/N): We need to go see if Aunt Nezuko is safe!

Dad: right

We ran up the stairs and to Nezukos room where we hear grunting from a male which we can only assume is another one of these people who was about to attack Nezuko but just before he could dad jumped in front of the attack that cut him through his abdomen making both me and Nezuko shocked but it gave me an opening to cut his head clean off afterwards I went to check on dad, looking for a pulse anywhere on his body only to find none which made me start crying along with Nezuko. A half hour after dads death me and Nezuko buried them in the butterfly garden next to mom along with hand-made grave stones for them I noticed that the sun would be rising soon so I took Aunt Nezuko back inside to her room seeing as she was already asleep

(Y/N): what should I do now that they're dead? I guess I should go to school since I have nothing else to do besides killing demons around town.

After that I decided to sign up for kuoh academy online seeing as thats my only choice and found out that I would be starting next week all I have to do is pick up my uniform from the school and I was very pleased to find out that they had a kendo club and a music club with a piano which I loved.

Afterwards a thought came to my mind that my sensei's left me something in case they died, so I went into Tanjiro sensei's room and checked the drawers for anything he might have left for me and soon I found a letter and it read:

Dear (Y/N)

If you are reading this than we have died, and if you are alive to be able to read this we are giving you custody over Nezuko and we already told her about this, I'm a giving you my sword and kimono which you will find in the closet in my, under the bed you will find a box, inside that box is something that belongs to you.

from:  Tanjiro Kamado, Zenitsu Agatsuma, Inosuke Hashibira, Mitsuri Kanroji

After reading that I went over to the closet and found the kimono Tanjiro sensei mentioned right next to a sword which I assumed was his, unsheathing the blade I was surprised to find a sword with a pitch black blade and it was the most beautiful sword I've ever seen. quickly remembering that there was one last item I went over to the bed and looked underneath it and quickly found a box labeled 'for (Y/N)'. opening it I found a black button up uniform shirt and on the back it said 'destroy', it was a perfect fit and I also tried the kimono which also fit perfectly and I went to show Nezuko how I looked.

(Y/N): Well Nezuko how do I look?

Nezuko than started to tear up seeing me as her brother, she ran up to my hugged me and started crying, probably because I looked like her brother we stayed like this until she fell asleep then I placed her down on her bed and put the covers all the way over her and went back to my room to sleep