If Deku Was Part Demon (Demon Slayers x MHA/BNHA)

Prologue

3rd Person POV
The story takes place 12 years before the main story. We follow a man who looked like the late king of pop. This man is none other then the evil Demon Lord Muzan Kibutsuji. He was walking down an alley like he always did. When he stopped.

"Why do you humans continue to get in my way?" He said, turning towards a group of men holding swords.

"Because you are nothing but..." but the leader didn't get to finish because his head was severed from his body. Soon the alley was covered in blood.

"Pathetic..." He started to say when he heard a giggling of a child. No a baby.

Muzan looked for the source of the noise. When he noticed a box covered in blood. He looked into the box and was meet by a pair of Emerald green eyes.

Muzan looked at the human child. He tried scaring the child with his aura, but instead of making the child cry it smiled a smile that could rival the sun and the child's pupils became splits like a demon. When Muzan saw this he became intrigued. The child reached out to Muzan. Muzan picked the child up and smelled the child's scent.

'He smells like a human, but I can also smell some demon blood in him.' Muzan thought,

Muzan was about to leave with the child but he noticed a note inside the box. He took it and read it.

To who ever finds this child,
This child's name is Izuku Midoriya. He is ⅔ Human and ⅓ Demon. His parents are dead. His father (human), was killed by demons and his mother (half-human and half-demon) die after giving him his name.

He has special type of Blood Demon Art that gives him multiple different powers. I only know some of them. He is immortal. He can't be killed by demon killing blades, demon killing poison, and he is immune to the sun. Here are the powers that I know of.

The first is called Black Whip, it allows him to make whips made of dark energy and control them like ropes or grappling hooks.

The next one is Danger Sense, as the name implies he can sense danger from a ½ a mile away. He can increase the range with training.

The next one is Float, basically he can float or fly.

The next one is Telekinesis, basically he can make anything move, but he can't Carry more than 20 to 25 fully grown people.

The next one is Telepathy, he can basically speak with others by his mind.

The next one is Teleportation, he can basically Teleport himself along with others to anywhere as long as he is given the exact coordinates.

The next one is Analysis, basically he can analyze anything. Be it other blood arts, Breathing Techniques, strength and weaknesses, or just making plans.

The next one is Judgment Smile, basically he can make his smile a weapon be it to humans or demons. He can make them speak out their problems.

The last one that I know of is Smoke Screen, as the name implies he can make different colors of smoke. Each color of smoke has it's own kind of effect. The effect can effect both humans and demons. Here are the colors and their effects.

Black; Hides the user and those he choose to become invisible while trapping others in a world of black this also messes with the enemies senses.

White; Causes people to see things.

Mist; Calming effect.

Pink; Healing effect.

Red; Causes people to become extremely hot and sweaty.

Orange; Causes extreme pain.

Yellow; Cause extreme rashes.

Green; Cause people to become sick, dizziness, and disorientated.

Light-blue; Causes people to become extremely cold and slow.

Blue; Causes people to fall asleep.

Violet; Causes Poisoning to anyone.

Please rise him well. Also the blanket helps him calm down. I hope you treat Izuku like your own kin.

~High Priest Daniel

After finishing the letter Muzan looked at the child in his arms. He started getting evil ideas about using the child but suddenly he received a vision of the future, but it wasn't any ordinary vision there was two paths.

One show him that Izuku would betrayed him and kill him, if he continued down the path he was thinking about.

While the other showed him a better future, but he will have to change up how he goes about doing things, but with Izuku's help he could reach not only his goal but something that he never knew he was missing. Love and Happiness...

Muzan returned from the vision and looked at Izuku. Izuku looked at him then he yawned and started to snuggle into Muzan's arms. At that moment Muzan made his decision. Grabbing the blood covered box he found Izuku in and walked away with it.

Word Count 816.