The perfect mistake (Highschool dxd x male reader)

Prologue

HELL.

For humans, when someone says the word hell they think of a place of eternal suffering, the home of Satan and the most horrible place to ever be.

But to the devil's and devil Kings, is the opposite, hell is their home, a place that for humans Is horrible, is actually not that different from the world that humans live in, just that in hell everything is possible because of the magic the devils have.

...

A mistake, good for nothing, powerless, weakling, waste of space.
Just some of the nicknames that a young little devil is called by his 'family'.

(Y/N) Gremory was neglected and bullied by his so called 'family' because he was different from them. The gremory's are more recognized for being one of the houses of the 72 pillars and for their red crimson hair.
However, young (Y/N) wasn't born with this trait, he wasn't even born with one of his parents traits.
When he was born he had (H/C) hair and (E/C) eyes.

The parents never knew why this had happened, when they got home from the hospital they threw him in the basement, when he cried they never went to see what was wrong, they fed him grumble of food and never gave him something to drink.

But when he turned four, the treatment got worse, they hit him, punish him for the littlest of thing and never helped him, even his older sister rias beated him and called him things.

He was never teached how to use magic, how to defend himself, how to fight or how to use his power of destruction if he even has it.
Instead he was teached lessons with punishment for the most stupid reasons.

Right now, the now 8 year old (Y/N) was in the basement of the gremory Manor curled up in a ball in a corner all bloodied and weak after another beating from his 'family'.
He cried hard by knowing that no one cared for him.

(Y/N): Why? *Sniff* Why do they hate me? *Sob*

Then, out of nowhere, the young (Y/N) heard a voice.

(???):You are going through so much pain aren't you little (Y/N)

The said boy gave a little jump Suprised about the sudden voice.

(Y/N):Who are you?

(???):Relax little one, I'm not going to hurt you.

This made (Y/N) relax a little.

(Y/N):Why can't I see you?Where are you?

(???): I'm inside your mind, and I'm a demon.

(Y/N):A DEMON!!!

(???): Don't yell, and yeah, I'm a demon... A demon of war to be exact.

(Y/N):What are you doing in my mind.

(???):You see... I feed of the anger, sadness and grief of a person and little by little make them Insane. But you... You interest me.

(Y/N):Why is that?

(???):Because you have potential... Potential of being very, very strong.

(Y/N):But how? I don't even know got to defend myself.

(???):In time I will explain everything to you. Now, tell me, do you want to leave this place?

(Y/N):Yes, but, how?

(???):If you let me control your body for a bit I can give you some of my power to leave this place and start a new life and I will show you how to become strong.

(Y/N) was a little hesitant to accept, because he didn't know if the demon was going to be true to his word.

(???):Don't worry (Y/N), I will give you total control of your body when we leave.

(Y/N) eventually accepted the demon's offer.

(Y/N):I accept

(???):Okay, now, I want you to close your eyes and think of letting me free.

(Y/N) did what the demon told him to do, closing his eyes moments later he was being surrounded by what looked like black flames then being consumed by them.

When the flames started to cease and he was visible his hair changed to black and when he opened his eyes they were dull, then he spoke in a deep and menacing voice.

(???):Time to give the gremory's a little scare.

Then he started laughing maniac lauhg.

...

In the dinner hall the gremory family was having dinner when all of the sudden they heard a loud boom coming from the basement of the manor.
Everyone jumped from their seats after the loud noise and got in a defensive stance.

Sirzech:What was that?

(Y/N) then broke through the floor below them causing them to jump out of the way.
After everyone got up, they all looked at with slight shock.

Ria's father(forgot the name):(Y/N)?

(???):In a way yes, I'm a demon who took control of his body with his permition.

Sirzech: That's impossible, All demons went extinct.

(???):All but one, and that's me, a demon of war.

Venelana:The strongest type of demon.

(???):You got that right, venelana. Now before me and (Y/N) leave this place forever, I'm thinking in doing a little destruction.

And with that, he curled up in a ball floating in the air and a powerful aura was surrounding him, the devils sensing the power of the attack that the demon was charging ran to cover.
When the demon got enough power he released it making a big crater in the center of the manor, but the rest was still holding.

Satisfied with his work the demon then teleported away, leaving the devils in the dirt.

...

The demon teleported to the woods in the underworld and then gave the control of his body back to (Y/N).

(Y/N):You didn't tell me you were the last demon alive, one of the strongest as well.

(???):I thought it wasn't necessary so I didn't say it.

(Y/N):Well, that doesn't matter know. What matters now is that... I'm free.

(???):You got that right, you have a big journey ahead of you (Y/N), I know.
And this, this is just the beginning of this journey.

(Y/N):Hey do you have a name?

(???): No, I don't have one, but if you want, you can give me a name.

(Y/N) gave a thoughtful him and then a name popped in his head.

(Y/N):How about.. Dark.

(???):hmmm, I like it.

(Y/N):okay, so... This is the begging of my journey?

Dark:Yes, indeed it is. It will be tough, but I know that we will make it, if your ready, start walking.

Your journey begins now

...

And done... This was longer than I thought it was gonna be.

So... How was it. Let me know in the comments

(Bonus song)