The following is the first chapter of a fanfiction type story that came to me suddenly, after having replayed again the Mass-effect trilogy with its legendary edition. This story will explore the following idea: What would have happened if Izuku possessed a Quirk that gives him the ability to be a Returner-type Isekai character? (someone who has traveled to another world, gained power and then returned to his own world, usually with those powers and abilities still intact)

And in this case, Izuku's Quirk sent his "master" to one of my favorite sci-fi Universes/Games, Whose main character, ironically, can be "edited" to suit the wishes of his/her "controller"...

...Anyway, I hope you find this short story entertaining. More clarifications of the doubts you may have, will be resolved in the following chapters. By the way, this story is also inspired by one of the chapters of the fic "What if" of the user "GreyTail" from the platform "Archive of Our Own", I recommend you to read his stories, they are very good.

don't forget to click the "favorite/follow" box to support the story. A review is also appreciated in advance, if you are interested in leaving your opinion about it.

Best regards!

Disclaimer: The characters and storyline of [Mass Effect] and [My Hero Academia] don't belong to me, they belong to their respective authors/companies. This is a fictional story created solely for the purpose of entertainment, and is not for profit.

Quirk (1): Returner

"Don't let them control you!"

"I Tried. Shepard..."

*Bang*- The illusive man was finally dead. A plasma bullet from a Carnifex ripped through his skull corrupted by alien technology and entered the only thing about him that was still human, his brain. It was a fitting end for the bastard, who at least had the decency to kill himself after all he had done under Reaper control. Shepard wished that bastard had suffered more but that involved time that neither he or Anderson had at the time. Warm blood dripped from practically every pore and his body just like Anderson's, he could barely stand upright

-o-o-o-o

Minutes passed and Anderson died. His loss was one of the most painful things he had ever experienced in his life. Although his life had never been easy, he never expected that he would feel so much sadness at a time like the one he found himself in.

But he didn't have much time for regrets because the wave of shit didn't stop hitting him. The citadel's device wasn't working, which left him with a feeling of frustration and agony that could have collapsed any other biological being...

...But not him, not at that moment, not in that place and not while he was still alive. He kept fighting, it was the only thing he knew how to do since he 'woke up' in this world. He pressed buttons and kicked the console until something finally happened. He doesn't know if he really achieved it by his own merit, if it was a coincidence or if just someone had been playing with him all that time, the only thing he knows is that he was taken to a new section of the citadel and then he could see an internal section of the crysol and the 'boy' who was guarding the place, Whose holographic appearance was almost identical to that of the child he was unable to save.

That was incredibly strange...

"Your time is coming to an end. You must take a decision"—...But the words of the child were even more strange and heartbreaking. For three years he had dreamed of destroying those sons of bitches who had brought so much pain to countless planets and living beings in countless cycles of creation and destruction, but now this child had just told him that the destruction of his archenemies would also bring the destruction of his synthetic friends and his entire 'lineage'.

And upon hearing that, Even though he hated with every fiber of his being the Reapers and their targets...

...He knew he couldn't do that to EDI. Legion's sacrifice was not to be in vain. The Geth had earned a chance to prove that they deserved to live and be free. Everything they had fought for was going to be lost if he destroyed those bastards.

The synthetics he knew were very different from the Reapers: they had feelings, dreams, desires and wanted to cooperate peacefully with organic beings. Even if they had not been born through an egg or a birth, he knew they were alive.

But more importantly, he knew that synthetics and organics could come to understand each other!. He, Legion, The Geth, EDI, Joker, Tali, Glyph, etc... They had all proven that it was possible!

He made his decision. It was incredibly difficult but he made it after his analysis came to an absolute resolution. He ignored the red light or the green light and then turned to the blue light. Destroying the Reapers was no longer an option and the last option that the 'Starchild' had proposed to him seemed too suspicious or fanciful: If what the boy said was possible, what would prevent the Reapers from controlling the will of the new technorganic beings that would be 'born' in the Galaxy? So before his life came to an end because of the deadly injuries to his body, he decided that before he took his last breath a copy of his consciousness would force the Reapers to obey his will for all eternity.

He would have liked that there was another option that could make everyone happy and that would have allowed him to continue living to be by the side of the people he loved but life seemed to have decided to screw him for one last time.

"Let's end this once and for all", With a completely tired and annoyed face in between he said those words and then walked agonizingly towards his destination.

-o-o-o-o

Before touching those cranks charged with a powerful electric current, he took a deep breath and then fulfilled his purpose. Then the horrifying pain spread through every fiber of his being but he forced himself not to scream. He would not grant the Reapers that satisfaction, at least his organic body would not give them that of itself before it disappeared.

As the pain continued to expand and as his body was vaporized, he thought one last time of the loved ones he left behind and/or would leave behind in this world.

Anderson. Thane. Mordin. His beloved Liara and Tali. And all his dear friends.

At the thought of them, the pain finally disappeared.

And a moment later as that comforting smile took over his expression, the freckled and green-haired commander, Zuku-Shepard, had finally ceased to exist.

The legend of the greatest hero in this galaxy had come to an end.

-o-o-o-o

But where one legend dies, another will always be born.

-o-o-o-o

Inko Midoriya watched as her son lay on the bed in his room with the heart monitor beside him still releasing the soft sounds of his heartbeat. She was gently stroking his hair.

"Oh my baby, my poor baby", Inko murmured, "You've already slept for 3 months. It's too much now...I can't bear this pain anymore...Come back to me please my dear Izuku. Fight. Please my baby, fight and come back to your mother."

Three months ago, just after his 17th birthday, Izuku Midoriya had been hit by a moving van while walking to school and had been in a coma ever since. Doctors were unable to wake him up even after the green-haired man's body was healed, so he remained unconscious and sleeping peacefully in a certain hospital room, until he was moved to his room in that apartment that was his home when hospital costs became exorbitant. With Izuku's father having passed away quite some time ago, Inko was forced to take out a large loan to pay for the treatment and hospital equipment needed to continue treating and monitoring his son's health at home. And since that move, two months and 19 days had already passed. She had tried everything to bring her son back: she got doctors (among other professionals) with various peculiarities to treat her son, from psychics who read his mind and tried to wake him up, to healers with all kinds of strange powers. And despite all of the above, Izuku remained in a coma.

Inko's current routine consisted of the following: she checked her son's condition every day, then washed his body, applied nutrients to the IVs connected to his forearms, changed his underwear, threw away his waste, shaved his head, massaged his muscles in the hope that they would not atrophy, regularly moved his position to prevent Pressure Ulcers from forming, etc. She always kept a constant check on the heart and brainwave monitors, hoping that someday she would see some change in them.

*Bip*-Thankfully, on this occasion her tears would finally have an answer as a soft beep interrupted the steady tone of the heart monitor, causing Inko to blink in bewilderment as she looked at the screen of the monitoring equipment.

*Beep*.*Beep*- Then, two spikes on the screen which measures brainwaves manifested themselves. *Beep*.*Beep*.*Beep*.*Beep*-and then there were more and more peaks and beeps...

*Boom*...until the machines suddenly stopped releasing unsynchronized and annoying sounds as for some reason they exploded after they were filled with a powerful electric current, which traveled in an instant from her son's body to the devices.

"Noooo!", At the sight of that scene, Inko shrieked in horror, thinking the worst. But..."Uh?"...As she turned her visual focus toward her son's head, she finally realized that her offspring's bright emerald eyes, had opened for the first time in weeks

"..."—The two looked at each other in silence for a moment. The corners of both of their eyes filled with water in no time and just as the tears began to drain, Inko reached over and then ran her hand gingerly over the green-haired man's cheek. She was so lost in her happiness that she didn't notice the faintly visible, luminescent scars that now adorned her son's left cheek and part of his forehead.

"Mother", Izuku said almost in a whisper, probably being cautious not wanting to take another disappointment caused by an illusion resulting from his strong desire to see her again. He had probably already thought a long time ago, that he would never see her again ,"I missed you. You don't know how much I missed you"

-o-o-o-o

A week after he woke up and once the curtain of night descended on this day, Izuku stared at the ceiling of his room and ran through in his mind the events that had happened in the last 7 days

He had had to spend an entire day trying to comfort his mother, who spent most of it sobbing with relief and happiness in his arms as they sat on the couch in his apartment, where they caught up in no time. Later, when she noticed the luminescent red scars on her son's face, she wasted no time and took him with great distress to the hospital where the doctors who initially attended him were. There, his brain waves were examined along with his other bodily functions through various medical machines and blood tests. Afterwards, he had to undergo a series of physical and mental tests while the doctors checked to see if the accident and subsequent coma had changed anything else.

Oh, and the coma had changed something else. In fact, it had changed many more things. The doctors, his mother and even he couldn't help but be surprised by that fact. Not only was he now approx. 1. 87 m, but the performance tests initially proved that what he had experienced in that other world/universe, had not been a hallucination caused by his dying brain or something like that, for not only did he perform so well in every physical or mental test, that he almost looked like a soldier who had been put on the Captain America serum, but in addition to those super-human physical and intellectual abilities that almost seemed like a peculiarity by themselves, he now also possessed a truly Quirk. A Quirk that at first he dismissed as a quirk, as he considered there was no chance of it being one even if he was also able to observe its effects in this world, but ironically the doctors confirmed (with blood tests) what he refused to believe

Not only had all the experience, will, memories, knowledge, muscle memory, physical strength and reflexes he had acquired as a Zuku-Shepard appeared as if by magic in his body and/or mind right after he woke up from his coma, but also something else had accompanied him from that other world.

"This is completely absurd! It doesn't make any sense!". Enunciating with great annoyance and a bit of sarcasm the above, Izuku flexed his hands, watching his muscles tighten and twitch beneath his skin. He still felt as strong as he did in the other world. No, even a 'little' stronger, physically speaking.

"Shockwave"—Thinking the above and saying that, he raised a hand and pointed it in the direction of a collection of toys resting on one of his desks. Moments later, he let the 'force' he felt accumulated in his 'nerves' flow and then all the action figures were sent flying as the wooden shelf was fractured into a thousand pieces by some kind of energy in the form of green waves.

Upon awakening from his coma, Izuku never stopped feeling the pulse of his Biotics through his nervous system, veins and tissues. The supernatural power that he had spent years training, cultivating and enhancing, was still there, although unfortunately he felt that his ability to use that power within himself, had returned to its beginnings, as if he could no longer release and/or control the true force that his Biotics were capable of exerting. However, now he felt more 'attached' to his power, as if he was even more part of himself than he had already been in that other world, so he very much doubted that these Biotics related powers were working with Zero element and/or bio-implants, as the mass effect waves were not supposed to have a green color; And most likely due to this change that his Biotics underwent, he was now not able to use the Mass Effect at full power; Apparently now his Biotics had become a Quirk and like almost every Quirk that awakens in this world, it had to be trained and mastered for it to reach its true potential.

"Heh", At once again, he smiled proudly as he saw the accomplishments of his recent action. All his first life he searched for some way in which he could become a hero; he tried to awaken his quirk for years without achieving any success, until a little over 3 months ago per his post.

Apparently he had finally gotten a way to achieve the most desired goal of his first life; Nostalgia soon caught up with him as he looked at the [All-Might] figures now lying on the floor; How long had it been since those days when he was an innocent child and a fan of the Heroes?

"How am I supposed to explain everything that happened to me? Am I supposed to tell them that I woke up in the body of my other self in an alternate earth of another universe? One where there were also strange powers born of quirks that respected the laws of physics? That I was in a world full of incredibly advanced technology? How are they supposed to believe that I spent over 27 years of my other life fighting aliens and monsters born of bio-engineering and technology so advanced, that most science fiction tales on this planet fall short? Yes, I'll definitely just let them believe that my physical condition is also due to the awakening of my Quirk, the Mass Effect...And I'll 'bury' the rest deep in the back of my mind"

Saying that, An errant thought wiped the smile from his lips, making him frown as his eyes watered.

*Sigh*-As he evoked certain memories he also sighed with great sorrow. He soon recalled all that he had lost/abandoned after leaving that universe; The incredible worlds and landscapes he had visited, the achievements he had made, the people he had saved, the companions he had met, the friends he had made and of course, the women he had fallen in love with.

In that place he had literally experienced another life very different from the one he had had as an Quirkless in this world: He still remembers that the first memories he has of that other universe are quite bitter because after waking up in the body of a 4 year old boy (whose appearance was identical to the one he had at that age) he realized that he was a laboratory rat and a homeless and orphaned child, whose only belongings were a worn out clothes and a metal necklace which carried a small silver plaque with the following information engraved in its center: "Shepard/Blood Type O Negative". To this day he still doesn't know if "Shepard" was his last name or his first name in that world.

In any case, he was 'raised' since he had memory on the streets of a certain big metropolis in that alternate Earth and in order to survive in that hostile environment, he was forced to abandon the morality he had built in his universe of origin; his childhood was filled with petty crime and gangs, which allowed him to stay safe and not starve to death. That was, until he decided to enlist in the Alliance army when he turned sixteen: Although he had become a delinquent who stole all kinds of items to survive and sometimes killed Gang members who deserved it, he always kept the dream of being a hero (at least in one way or another), so he thought that enlisting in the army would at least allow him to save other people. And after a few years, his career in the army became so epic, that he barely has words to describe all that he had lived as a cadet, a soldier, a sergeant, a lieutenant, a captain and a commander: A commander who at the young age of 31, had achieved the impossible; Uniting an entire galaxy against a common enemy. An enemy so incredibly dark and powerful that it had caused untold death and destruction for hundreds of thousands or perhaps millions of years.

And in the first hours after he had returned to his home universe, he at first tried to delude himself into thinking that what he had lived in his 'dream' had been just an incredibly realistic hallucination or lucid dream, but unfortunately he couldn't live in denial for long: He knew that there was no way his imagination/mind had the capacity to create such a detailed and realistic 'dream world' and the subsequent evidence that he retained his body was the undeniable fact that somehow, the supposed Quirk he had been told he possessed (since he was tested at age 5), was about some kind of ability that exercised the powers of the archetype of a 'Returner' character from the classic Japanese tales: Someone who has traveled/been reborn in another world, gained Atributes/powers and then returned to his/her own world, usually keeping those powers intact and at other times obtaining variations of this powers, adjusted to the physics/logic of his/her reality of origin.

Probably, his peculiarity had finally activated at the moment of his accident and had sent him to be 'reborn' in another world to later bring him back together with all the attributes gained in that other place: of course, his peculiarity gave him all of the above, after his purpose in that other world was fulfilled and/or after his other self absolutely died; Or at least that was one of the possibilities his mind conjured up after trying to make sense of what had happened to him in that other reality and what was happening to him in his universe of origin; Another of the possibilities that he also thought of (besides believing that maybe he was still in a coma or that he had already gone completely crazy), was that maybe his Quirk was really just some power that enhanced his physical strength and reflexes to a super-human range and that in reality, the scars plus the Biotic abilities and the Omnitool on his left arm were the result of the blatant and cruel Prank of some kind of divine entity who was too bored and too lazy and bitchy a son-of-a-bitch to show up and/or explain his game plan to the rejuvenated green-haired man.

*Sigh*-After a few minutes spent in contemplation, he once again sighed heavily as he stood up. Crying and feeling sorry for himself and what he had lost was not going to bring back the things he loved from his former life. And if he learned anything very well from that life, it's that the only way to endure pain and move forward, is to stand up and keep fighting. Value and remember the valuable things from the past, learn from them, but don't get stuck in the past or you will break; Keep moving forward and keep fighting until you create a change in yourself or in the world around you. Keep fighting...That was the only way he knew: It was his Mantra.

After several minutes of repeating those words to himself, when he finished dressing in sports clothes, he decided to leave his house. He inhibited the melancholic thoughts of his soul, and for mental health he forced himself to continue forward; he forced himself to build a new future for himself and for his mother in this universe. So he had to restart again his first life; He decided to Restart the path to those dreams he once had in this world and at the same time, he set out to make the necessary changes that his first life greatly needed.

-o-o-o-o

"Well, this seems to be on the right track", Izuku muttered as he stretched his muscles. He was currently standing on a shore of Dagobah beach, looking at the remaining trash that covered the sand of this place, though only 2/3 of the junk that had turned this place into a dump remained ,"Just as I thought, it's turning into a good exercise routine"

*Metal Sound*-At once, he flexed his arms in front and then placed his hands on either side of a broken refrigerator: Less than a minute later and with some difficulty, the refrigerator was finally crushed by those strong hands and then turned into a piece of scrap metal resembling an imperfect ball of metal as the green-haired man molded it into something that could be carried more easily. He still felt as strong as in the other world, although strangely, that physical strength that with hard work and dedication he had managed to cultivate in his military training, was reflected in this universe in a slightly stronger way than he remembered. For some reason, some of the combat stats he retained of Shepard, such as his physical strength, in his home universe seemed to behave in a different way compared to the other plane of existence. He was probably now as physically strong and durable as a 'Yahg': He certainly had a feeling that the walls of a building would suffer if he threw a punch at them...

...When he realized the changes in his physical strength, he analyzed that perhaps it was due to the fact that the laws of the Genetics of the human beings of his reality of origin, had characteristics even stranger than that of the biological beings of the other plane of existence for after all, in his universe of origin, the genome of his species could give rise to powers as strange as the Biotics or even stranger powers than those, for they could alter the laws of physics/chemistry/thermodynamics, etc. to a great extent.

And there were also Gifted human beings whose bodies had been 'refined' by their Quirks to such a degree, that they seemed to have a second or third peculiarity in addition to the one they already had, even though the other components of their body, didn't possess supernatural power at all. For example, he had seen how the arms and hands of that guy he claimed was his friend, had become so strong as to withstand those terrible explosions and it was likely that the rest of his body was also able to withstand the shockwaves of his own Quirk, which shouldn't make any sense given that the other components of that body were completely human; However, due to that 'lack of common sense' in the normal genome of the humans of his universe, it was very likely that a human being without a quirk, could go on to develop superhuman attributes if he or she demanded his/her body to go above and beyond with a crazy and risky exercise routine ... .

"If only I had known that I could be a hero just with an exercise routine as absurd as the N7 training, I would have started training since ... *Sigh*...Meh, it's not worth thinking about that anymore". He quickly abandoned that line of thought when he recognized that he couldn't change the past, so he decided to continue with the training of his body and peculiarity.

He then hit with the green energy spheres that came out of his hands, three pieces of semi-spherical metal scrap (that he had created by manually bending scrap) that were near him and then after they were wrapped in a green aura (after they were hit), they levitated at ground level. That done, he charged those objects with great ease and then ran 3 km towards that large trash can as fast as he could, before his Biotic skill, [Lift], stopped taking effect on the objects. Approximately 20 seconds later, a washing machine and 3 decomposed and manually compressed refrigerators were correctly deposited into the industrial trash can.

"[Lift], still behaves in the same way as on the other plane of existence. It generates a sphere of energy that reduces the Mass of whatever it touches, so it will reduce the weight and even make objects, allies, friends, enemies and other things levitate, as long as the sphere touches them. Hmmmm, however, it seems that the levitation range has weakened and so far I have not been able to strengthen it. My body and mind don't seem to respond to my desires and I am still unable to deposit all that 'energy' inside me. It also seems that my stamina is drained a little every time I form a sphere and I am starting to feel a headache and muscle aches...How strange... Hmmm, is there another way to deposit that 'energy' into the sphere I form?...or is my inability to make the effect of this sphere stronger due to my lack of training with this Quirk? Or should I just make my body and my Quirk even stronger and then imagine a more powerful sphere? The Mass Effect peculiarity will have other limitations or variations in this world compared to the Biotics of that another universe?...*Blah* *Blah* *Blah* *Blah* Aaaaah, Too much lack of information *Sigh* I can only continue exploring the characteristics and scope of my powers... "

Said that, the green-haired young man sighed in defeat and set out to continue his training with clear goals in mind: He wanted to completely master his peculiarity 'Mass Effect' (Or Biotics for short) and at the same time. He wanted to push the strengths of his body and mind to the limit.

He wasn't someone power hungry like the illusive man, but if he could keep improving himself he was going to try. All with the goal of becoming an all-round Hero, ready for any kind of situation; Not for nothing he had trained (in that alternate land) as a Sentinel; A Biotic Soldier who also knew enough about Technology and Engineering to use it on the battlefield by utilizing a diverse amount of technological talents that favored him.

*Boom* *Boom* *Metal sounds* - A few minutes later, metal screeched loudly on the beach of Dagobah as a car was collapsing in on itself due to the heavy punches of the boy, who most likely wanted to turn the old car (he had found) into a compressed ball of scrap metal.

In no time, fragments of metal were scattered across the sand and then Izuku's smile became very wide. He knew he would be ready for the U.A. entrance exam, but would this exam be ready to meet Commander Shepard?

To be continued...

Library:

(Section created to solve doubts and/or place skills revealed in the chapter and/or some other information of the characters shown in the story. Read the following keeping in mind the voice of BKNHA's peculiarities presenter)

Quirk!: Returner!: The peculiaritie always possessed by Izuku-Midoriya, awakened at the moment he suffered a terrible accident. It exercises the powers of a "Returner-type Isekai Character", in a limited way when he has fallen into a coma and/or suffered an accident that keeps him asleep for more than 48 hours; which gives its user the ability to send his Consciousness to another plane of existence, chosen at random, as long as there is a variant of himself in that place: This variant will then be possessed by the "Returner" user, who will be able to live a second life in that another world, if desired. The moment the Quirk deems that its user has fulfilled its purpose and/or every single neuron of the possessed body dies absolutely, it will return its user's consciousness to its plane of origin and then alter its cellular and molecular structure to grant it all the bodily attributes that its user has attained in that other world.

The Biological Powers obtained will be modified in a peculiarity, while those things that don't possess a link to the DNA and/or Biology of their user, such as purely technological implants will be converted in the same manner in which they were used and/or obtained, while retaining all stored information.

Since the laws governing the Quirk World are obviously different from the "transfer world", the physical attributes obtained such as physical strength/Durability/Stamina/Speed/Reaction Speed/Reflexes/Sense Acuity, will behave differently in the Quirk World. But even though all of the above probably makes this Quirk the most powerful quirk in Technical terms, the following limitations must be taken into account:

The first; if its user dies in his/her universe of origin, it will be impossible to bring his/her consciousness back from the world to which he/she was transferred, so he/she will be trapped forever in that place.

The second; The Quirk modifies itself to be able to grant to its master, the Powers/Attributes that He/she cultivate in that other plane of existence, so after this Modification occurs, "Returner" will no longer possess the ability to send its user to another World if he or she becomes comatose again and/or if he/she sleeps for more than 48 hours after suffering an accident. So "Izuku Midoriya/Zuku Shepard" better not die for the third time or he will definitely stay in paradise forever!