It is my first attempt in a highschool dxd, ben 10 and my hero academia crossover fanfiction. So if you find any problems feel free to tell me.

In mha universe

"Sorry boy, you cannot be a hero without a quirk" all might said to izuku.

Unknown to them a certain man wearing a lab coat and a stop watch hearing in the conversation. He was professor paradox who became an immortal time traveler due to an accident. He saw how the hero's words broke the boy. He did not help but pity at the boy. He decided to create an alternate universe by helping the boy.

He then opened a portal and came into another universe.

In ben 10 universe

Ben 10k was bored and he did know what to do. Then a portal was opened in his house which was in space (in ben 10 omniverse future headquarters).

Ben was very happy to see paradox. "what do you want paradox, you only come here if you need my help or my son Kenny's help".

"I'm hurt ben , did you only think I came here for only asking favors. But yes, I really need your help in another universe."

"why did you need me, ben prime was more powerful than me due to his each decisions change or creating timelines."

"No ben, I need your help in another universe, not in benverse or any of your other timelines. We are going to an universe with timelines called dekuverse."

"tell me about the universe"

"do you know anything about one above all, ben?."

"yes, he is the entity beyond the multiverse that can immune to celestialsepians."

"Right ben, he created some universes that away from the Zeno cult."

"who was the Zeno cult?"

"it was one of the children of one above all who have the control over 12 universes."

"OK"

"then back to the topic one above all decided to create a universe with quirks"

"let me guess, this universe have people have special abilities."

"you guessed it right ben, but I need the original omnitrix now. I heard that Kenny decided to become his own hero by using the time belt I give him and he wanted you to give it to someone who fit for it"

"yes I'm proud of him now, but why do you need my watch?, unless.."

"yes ben, let me clarify in this universe there is a hero license system that is given by the government to act as a hero."

"but"

"i know getting paid for being a hero isn't that hero like, right. Kind of like the government registration act in civil war comics."

"yes, you are right and let me guess this, you want me to give the watch to someone normal and a loser like the child me but who have the potential to be a hero right?"

"yes ben, you proved yourself that why ben 10k is known as the matured and the intelligent ben in the benverse. The boy has more potential but he is going to get a power that very powerful but not enough to make it alive in a certain timeline of his"

"let me guess this also, you want me to give the omnitrix to him to add extra weapons in his arsenal for him to survive, right?"

"yes and no ben, in this timeline the dimensional gap also knows at absolute null void in here where once the infinity dragon and the great red dragon lived. In their earth the all mythical factions created by humans are true. It is the reason why we need to make a new hero apart from the fake heroes in that world. Do you understand ben? "

" yes paradox, but why do you need me? You have to give the watch and show him how to be a real hero, right?. "

" No ben, what I need for him is a mentor. I will tell you what to do and you have to just do it ok. Now pack and tell your wife that you are going on a mission"

"kai died in this timeline after giving birth to kenny paradox, are you slacking?"

"No ben, I came to the right timeline you are going to packing all your things"

"why"

"because this new universe is going to be your new home"

Ben thought about it and decided to give this timeline a try. He sent goodbye to all friends. But asmuth find him before him and gave him the sword absolute excalon which is the fusion of Excalibur and absolute ascalon which is made personally made by asmuth as a parting gift.(he also received many gifts from other - explained later).

After a big party with his family he entered the portal paradox opened.

MHA UNIVERSE

'mustafu town'

The street is full of explosions. A blond haired boy was captured by a slime man. The big was Bakugou katsuki - the built and former best childhood friend of midoriya izuku.

The heroes done nothing. Kamui woods froze at the sight of the fire. Mount Lady was too big to enter the street. Allmight's time limit was over and he was in his civilian form as toshinori yagi.

But a green haired boy ran to save Bakugou. He was izuku midoriya. He throws his bag onto the slime man. This give some space to the blond boy to breath

The heroes tried to stop him because it was dangerous. Even katsuki growled "I don't need your help deku(defenseless izuku)".

But the reply of midoriya izuku made the true heroes to notice him "I didn't like you, but my legs move on its own when I see you asking for help"

Hearing this yagi decided to buff up to all might and save the day. But before he could change he heard a mechanical shout

"BIG CHILL"

He turned and saw it was a blue moth like man who he assumed to have a mutation quirk. The man just went and blowed some air from his mouth. The air completely frozen the slime man. Then he pulled the two boys from the grasp of the frozen slime.

Bakugou was praised for his bravery where izuku was berated for being idiotic. Seeing this the moth man who the heroes now arrested for doing vigilantism just become intangible through the cuffs and went outside and change into ben without seen by anyone.

He went immediately to izuku who just gone into next street and called him. "HEY BOY".

PLEASE GIVE ME A REVIEW.