so this is an idea I've wanted to play with and I hope you guys like it as this will mostly be OC centric and that's really the main pairing I'm going for is izuku x OC so if any of you guys have tips on how to write romance please let me know because I'm kinda struggling that department.

anyway with that said please review and tell me what you enjoyed or didn't like.

"When you've been alive for over two hundred years you learn that every little action doesn't matter that time you said hi to someone doesn't really matter in the long term scheme of things. hell, what humans considered long term I consider short term a decade being a long time for humans was, only short term for me." a mysterious figure said in a monotone voice. the figure looked over to the right to see yuuei high where fledgling heroes go to learn to become the greatest one of them all.

he seemed to stare intently at the building far away from the main campus until his eyes widened considerably he jumped the barrier faster than any security could detect and began running towards the dome-shaped building. on the way he ran past a matter suit of armor shaking his head he would just have to do a diagnostics later right now he had to find them and once he found them he could finally do what his dead creator wanted him to do.

(Aizawa pov)

if he could describe today's events in one word it would be fuck. why well because villains had attacked and now they were all lined up ready to be killed if all might didn't show up soon. his arms were broken in ways he didn't think were possible and they were getting ready to start killing. "come on why can't we just kill them already" one thug said.

"because the boss said all nights the main target"

"ya, but what good will any of these do alive how about we kill some of them."

Aizawa could feel some of the kids grow tense that last remark.

"I don't see a problem with killing a couple of the hostages." the second goon said while holing up what seemed to be a gun.

damit Aizawa had to think fast or some of the kids might really die but just before he could act one of the guards stabbed him in the shoulder. laying on the ground covered in his own blood Aizawa could only watch helplessly as his kids were about to get slaughtered but just be for the villains could do that a wight figure jumped down and began to ruthlessly dispose of them he seemed to stab his hand through the first thug. he then proceeded to do the same to the rest of the villains to quick for them to even register soon it was only the three ring leaders left.

"oh, we have a new one left nomu kill him."

faster than anything of the nomu's size should have been able to walk it punched the white figure in the staircase. everybody felt that hit but surprisingly it just stared at the nomu seemingly asking if that's all it could do. it tilted its head and uttered a single phrase "combat mode activated". then it seemed to grow spikes all over its body and then its arms seemed to get longer it then speared its and through the villain ripping a massive hole through the villain's chest.

"haha, you idiot the nomu was meant to take on all might it has regeneration."

to the untrained eye, it looked as if the white thing widened its eyes in realization but Aizawa knew better it was scanning for something. the creature then pulled back its right arm and the fingers grouped together creating a cone-like thing with a needle sticking out of the middle finger. then it decided to try the same trick again. punching a massive hole through the villain's chest again it spoke in a calm and quiet voice " compound C-34 anti regeneration."

that made everyone's eyes widen as it was really hard to counter really strong regeneration because it literally protected the user from nearly anything sort of death. they all looked at the creature only to see the thing with around in pain as its regeneration struggled to fix the damage but still kept it alive so it was forced to remain alive as it stuffed with a massive hole in its chest. the white thing looked at the creature before slowly walking to it and completely destroying its head.

"you... you... you cheater you will pay for that" then the villain charged at the figure only for the figure to grasp the guy by the throat and it was slowly choking him.

"tomura" the mist villain called out then his mist began to cover the figure only for the figure to prove just how much of a powerhouse it was. the figure grabbed the mist villain's metal guard and using the same needle attack it used on nomu it spoke again "compound c-45 anti teleportation" and just like that the mist villain fell to the ground glitching and just struggling to stay in one place. truing around the figure rounded on the hand villain grabbing the guy by the throat the villain grabbed the thing's arms only to cry out in outrage.

"how you should be dead"

"compound c-22 quirk immunity" and as if that was an explanation it drove its hand through the villain's gut not with the intent to kill but with the intent to do crippling damage. all of a sudden both the hand villain and the mist villain began to cough up a strange white substance then they were engulfed in the substance the white figure made no move to stop them but that was just before the heroes got there.

BOOM

"NEVER FEAR WHY BECAUSE I AM HERE"

then all might rushed and punched the white figure what surprised everyone was how the figure stopped the punch with little to no difficulty. "AH I SEE YOU ARE STRONG"

but before all might could finish it the figure used the same overpowered needed move it used on the villains and just like the other times, it spoke "former user of one for all detected compound c-35 needed" and with that, it moved faster than even all might could see and stabbed him in his left side. while that side might not seem important only those who knew Toshinori Yagi would know that that was his ultimate weak spot. everyone watched as the white figure began to neal in front of the convulsing all might as if it were pledging allegiance.

after a minute of watching all might within agony, they saw as he pulled up his shirt and revealed the ugly scar that was on his left side began to deform and go back to his original shape looking not only bulkier but healthier. the white figure they notice began to change too. its pikes that were on its back receded and the spikes on its head began to fall reviling log beautiful bright grey hair. and a small nose with big dull grey eyes then it revealed a body figure, not unlike jirou's own body.

she then moved over to the injured students and began injecting them with the same compound she used on all might end when she finally got to Aizawa she stared at him intently for a few minutes she then spoke up "compound c-35 and compound c-39 needed."

then she proceeded to inject him two separate times and Aizawa's eyes have never felt better she even got rid of his dry eye looking up at her he saw the blank face and whispered "thank you" her eyes seemed to soften as she nodded. she looked over the students, she had just finished checking and healing. she looked down at him and opened her mouth only to be silenced as a loud bang rang resounded and snipe was shooting at her however unexpectedly she just stood there and took it, staring blankly at the pro hero.

"wait stop she's friendly" Aizawa started yelling before it got out of hand.

"oh sorry, miss" snipe said embarrassed.

"oh it's nothing," she said as her body seemed to regenerate. all might began to rise after his agony finally ended.

"ah, young miss I need to talk to you privately" with that all might began to lead her away from the main group. "so how do you know about my quirk."

"oh my creator told me all about it, my main mission was to find the users of one for all and devote my life to them, but sean as you no longer have one for all I need to know who has it now."

"ah, I believe you have met him his name is izuku midoriya the one with the broken finger."

"oh that explains a lot... well then it's up to me to become his partner," she said with no hint of emotion as if this were a simple business deal rather than the lifelong commitment she made it seem like.

"if you don't mind me asking how do you plan on teaching him to use one for all."

"oh no that's not my job that's yours. my primary function is to assist the one for all users in any way shape or form."

"How exactly will you help izuku. while I'll admit your strong enough to take a hit from me you still have a lot to prove before your strong enough to go toe to toe with all for one." he crossed his arms in a show of being right only to collapse to the ground.

"oh, you miss understand me I wasn't created just to support the "chosen one" she mocked the title izuku now held "if he fails it is my secondary duty to step in and take over as I'm equipped to deal and handle all for one. so I'm in no way shape or form weak and if how quickly I paralyzed you is any indication all for one is just one bad day from being a true myth."

"ok can you please undo paralyzes on me?" he spoke pleadingly

"you should be fine in about ten minutes. in the meantime, I will tell you of my three forms. this is my gamma form the one I fight in is my alpha and I have a third form that is called my beta and I essentially become an armor that can sustain the life of the wearer."

"wait how old are you."

"I've been there from the very beginning"

that statement angered him "where have you been all this time If you were supposed to support the users of one for all then why didn't any of the past users mention you and why weren't you there to stop any of them from dying at the hands of all for one."

"well, I'll have you know that while the users of one for all were foolishly picking a fight with all for one I was traveling around the world so I could obtain the blood of every type of quirk on this planet if I had come sooner I would have been incomplete and something tells me you guys didn't like when I used my harvester to deal with those villains. so don't blame me for nanas mistakes not to mention the lengths my master went to just to make sure the users of one for all didn't end if not for me all for one would have ended year ago"

that remark about nana pissed him off but deep down he knew she was right. then he actually listened to what she said: "wait what do you mean one for all could have been ended."

"well I have the ability to replicate one for all and pass it on to the next user hell I can even be a user however the world doesn't need an immortal symbol of peace. at that point, it would just be stagnant plus I'm meant to help the hero not be the hero" then why don't we make an army of one for all users."

"because there is and will only be 1 one for all if I were to make another one then it would just destabilize both of them as one for would have to choose between both of them and in the process, both would look like they both had a successor as their power would drain then the 1 one for all picked would suddenly just explode with power rising the possibility of the death of the user. so long story short it's very stupid idea to even attempt to duplicate the quirk."

they sat in silence until all might spoke up "so what will happen now"

"well, I'm going to go and follow izuku and assist him while you can do whatever you want provided that it doesn't harm izuku in any way shape, or form."

they started walking back to the group in silence. turning the corner she saw izuku and eminently rushed over to his side. nealing down she began to pledge her servitude towards him. "izuku midoriya I offer my mind-body and soul to you. I shall assist you in your endeavors in every way possible." she said neutrality not a hint of emotion in her voice.

he stared at her for a long minute until Mineta first broke the silence. "you lucky bastard" he managed through bloody tears.

"um y-y-yes wait what"

"hahaha oh my god that's so funny"

and just like that everyone began to laugh at izuku's awkwardness.

"she however was very happy she managed to complete the first mission her creator gave her."

and done so please let me know if I should continue this or if you guys have any suggestions and I will put down a list of the current compounds and what they do if how they were used were confusing.

compound c-34 anti regeneration (when injected it completely nullifies all cell growth stopping the cells from regeneration)

compound c-22 quirk immunity (when injected it causes subject to become immune to all quirk effects)

compound c-35 regeneration (when injected it allows subject to have temporary hyper regeneration)

compound c-39 eye enhancement (when injected it allows subject to have fully repaired and enhanced eyes)

compound c-48 temporary paralysis (when injected subject is paralyzed for 10 minutes.

anyways thanks for reading hope you guys stick with me as I try to tell a good story.