The Green Beast

The beast from before noticed Izuku staring at him with determination in his eyes, this caused him to smile slightly, the beast crouched slightly and jumped straight at Izuku landing right in front of him causing Izuku to fall over.

When the beast spoke it sounded a lot less threatening than before, Izuku also noticed the slight smile on his face.

"Host is braver than I thought, but Host is not strong enough and Host is too small,"

Izuku quickly stood up and asked a question that has been on his mind for a while, "Are you my Quirk?" The beast looked to be in thought for a couple of seconds before nodding "You could say that I am your quirk, but you are not qualified to use my powers,"

Izuku looked at the ground before looking back up at the beast with even more determination visible in his eyes "How do I become strong enough?", the beast smiled even wider at this and said: "First of all Host's body is too young and second of all Host's body would break if Host used my powers so Host will do exercises and FIGHT!" the last part was shouted which caused Izuku's ears to ring.

"My name isn't Host" when Izuku said this the beast scoffed at him "I don't care about your name, as long as you aren't stronger than me you don't deserve to be called by your name." Izuku pouted at this.

The beast started speaking again "We will train here as long as you are asleep in the real world, whenever you sleep you will end up here and the training you do here will be the same as if you did it while awake, but this could be a little faster and less tiresome for some parts but you will still feel all the exhaustion and hunger your body goes through."

"So as long as I'm asleep, I'm gonna be here?" asked the slightly confused Izuku]

The beast just nodded at his question and told Izuku to follow him.

They walked for about 20 minutes until they reached a huge wooden house, as they entered there was only a single open space with no walls, in the corner of the room there was a single bed and the rest of the house was littered with martial arts weapons, countless swords, spears, and all sorts of weapons were both hung up on the wall and on the ground.

Izuku looked on in amazement when he tried to touch one of the weapons his hand was slapped away by the beast, while disappointing Izuku could understand that these weren't toys, this caused the beast to give him some respect for his decision-making skills.

While this was happening Izuku was already in a hospital room, and even though his muscles stopped twitching, he didn't seem to stop growing, he was now almost double the size he was before, and his hair turned to a darker green, even his skin was starting to get a slightly green hue to it.

Back to where Izuku and the beast were, the beast instructed Izuku to multiple exercises, although Izuku wondered if it would do more damage than good the beast just told him not to worry about it.

Izuku was currently standing in a horse stance, much to his disappointment he couldn't keep the form for more than ten seconds, his body wasn't developed enough just yet, but the beast told him to not give up and keep doing it, while Izuku was training his body the beast was looking through his wide array of weapons searching for one suitable for Izuku, although he was too small to wield anything big he should be able to use a knife or dagger.

The training continued for a total of eight hours, every two hours they had to stop for at least 30 minutes because the stress was too much for Izuku's body, the beast also got him some food, namely the deer that was just ripped apart by him, and it tasted surprisingly good, although it lacked some seasoning the fried meat was still good enough for Izuku, the water they drank came from a stream not too far away and it tasted surprisingly fresh.

The only thing that Izuku didn't enjoy in this place was the sun, it was a lot hotter than the normal sun and it was a lot bigger too, although it was colored the normal yellow it looked at least 3 times bigger, and all the sweat dripping of Izuku's body hindered his movement as it made his clothes stick to his skin so Izuku decided to only wear the shorts he was wearing.

His body wasn't very muscled and not even a sign of growing muscle could be seen on his body, and even though he ate a lot more than other children he still wasn't even a little bit chubby or fat, there was only a sign of baby fat on his cheeks which just made him cuter in his mother's eyes.

After 8 grueling and painful hours, Izuku woke up to a sound of consistent beeping, after a minute or two he got irritated by the sound so he decided to rip off the cables that were stuck to his body, and not even half a minute later multiple nurses and a doctor were rushing through the door to check on the child and if needed restart his heart.

Luckily they had nothing to worry about as it was Izuku who ripped the cords of off himself.

The doctor sighed and smiled at the young boy in front of him, "Young man, you gave us quite the scare there, your mother has been called already and is on her way, now is it alright if I ask you some questions?" the doctor spoke with a soft tone.

Izuku nodded at the last question the doctor asked the doctor smiled at this and proceeded to ask Izuku some simple questions including if Izuku still remembers his name, age, where he lived, and who his mother was, Izuku answered all of these and then the doctor asked the most important question, "Do you remember what happened when you fell asleep?".

Izuku looked to be deep in thought and then looked back up at the doctor, "I remember that there was darkness, and a large green beast, and when I fell asleep for the second time, I was in a cave but then I went out of the cave and then I saw the beast again but this time he wasn't as scary and we talked, he told me that he was part of my quirk."

The doctor nodded at this and asked another question, "If by any chance was this beast colored green?", Izuku was very surprised that the doctor could guess the beast's color, "H-how did you know?" Asked Izuku in surprise.

To this, the doctor just pulled out a mirror and what stared back at Izuku was his face, his green-colored face, his hair was shorter than before and an even darker shade of green and all the baby fat was seemingly gone, the robes which he was covered in part slightly revealing a ripped body, muscles that looked harder than steel and his whole body was colored green.

Before the doctor and Izuku could continue their chat Inko Midoriya burst through the door jumping straight at Izuku who with slight difficulty caught her and put her back on the ground but still hugged her back.

The doctor wrote something down on his notepad before leaving the room leaving the two Midoriyas alone in the room.

Izuku told the same things to his mother as he did to the doctor, and she was very surprised to hear that his quirk did this.

And to both of their surprise, Izuku seemed to shrink back down to his normal size almost on will, and even though he felt more comfortable in his green skin his mother told him that she would need some time to get used to it.