A/N: Hey everyone! This is a crossover! My OC from my fic OPM: Vei Rin and BNHA, meet! :DD

I've always wanted to do a Crossover fic so I decided to, anyone who hasn't read my OPM fanfic-- Feel free to do so if you want to have a full understanding of my OC :3!

If not, then I'm sure you'd be able to understand her in this one, it'll just take a bit of effort I guess. xD

And to add-- Slow updates are unavoidable ):  This is just for some fun of my own and whoever wants to read, I hope you enjoy it! :3   

Disclaimer: I do not own any of the MHA Characters, only my own OCs!

Warning: If you haven't read my One Punch Man fic with her in it, yet, then if you're sensitive to D.I.Ds-- I'd suggest that you turn away or be prepared. xD

There's nothing super serious or really triggering thus far, so please let me know if there is; I could make a Trigger list for other readers. :)

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On a peaceful night, the rays of the moon beamed on a young woman's pale complexion. In a black-striped and white outfit, stood the very feline herself. Those enchanting emerald slits gazed upon the bright moon with awe as she pondered on the future with her boyfriend. Saitama, her beloved Genos, and Sonic... After Gratta Quall's defeat, she has become far more open to the three than anyone else in her life and grew a little closer to Mumen Rider, whose real name was revealed to her one day at a birthday party Vei attended a while back.

Everyone decided to make plans to have a friendly group outing, something to get away from it all for a while even though it'd probably hurt their reputation. For Vei and Rin though, they only cared to be a Hero for the pay... In her hands were her and Vei's suitcases full of clothing and her guns. Though, the guns wouldn't all fit in the same case-- she had to get another one.

Those emerald, robotic hues looked down at the suitcases in her hands, she just hoped her pay wouldn't reduce for being gone a while. "I wonder-- if my mother and father will be alright..." her words were barely audible, whispered even, and a hint of concern in her nearly emotionless voice. Yes... Of course, they will be, my teacher and my parents are good friends now. Aside from that... her quiet monologue paused for a moment and left out a sigh of relief, once her gaze met the moon again. Vei and I both asked her if she'd watch over them, they're in safe hands. adding to her thoughts, those enchanting emerald slits closed in thought, remembering the moment as if it were just yesterday.

The masked woman was about to leave the rooftop of her home, until, a strange crack behind her met her ears. Like glass or ice cracking, Rin turned around just to see a large black fissure in the air with a glowing white aura. Her slits thinned, surprised at seeing such a thing, however--

What she wasn't expecting was for suction to pull her in so strongly, and that not even her attempts with her incredible strength to break free from the force, would work. It was so powerful of a suction that it broke up pieces of the rooftop and even a nearby streetlight. What is this?! What's going on?! In her mind, panic, and a rise of fear, filled her mind. By the time she reached the mouth of the crack, she was sucked in.

However, one thing was left behind; residue of her disappearance, scratch marks from the metallic claws that she extracted on her way towards the crack to try and prevent getting pulled in. Long streaks of it trailed down to where the fissure had disappeared and marks of struggling could be seen as well.

The boys never knew about her disappearance until later that day, which the feline herself wasn't aware of. Now, through the blackness of the abyss, Rin silently floated through the nothingness with pure shock written in her eyes. How is this possible? Saitama, Sonic... Genos! My parents, my teacher, won't know what happened. in her mind she panicked with disbelief and her slightly mature but quiet voice echoed.

On occasion, she would hear distant cracks like earlier and saw one close by but watched it fade as fast as it appeared. Something's not right... This place; a crack in the air? Being sucked in like this-- her mind contemplated the issue at hand and tried putting two pieces together. What was it that Genos once told me before-- when he was telling me about certain scientific theories I asked him to look up? again, thoughts swarmed her mind as she lay there motionless.

Those emerald eyes closed in thought, trying hard to remember what she asked Genos, and did her best to keep herself calm. Recalling moments in her life after Gratta's defeat and becoming a Hero for the pay, nothing really came to mind until she pondered harder on the long fissure. At that moment, her gaze snapped open, lighting up with surprise at realizing what it was she asked.

"A crack-- in my dimension...? I've heard of wormholes in space, but cracks in the air? It feels like these odd fissures are somehow similar to wormholes considering it sucked me right in," mumbled words left her half-covered lips and hid most of the astonishment on her face.

Another sound, like glass or ice snapping, her head whipped around like a cat to a mouse, and saw the very same crack from moments ago. This time she spent no time thinking, instead, the woman chose to hurry her way across the emptiness of the void to reach it and mentally prayed that it wouldn't fade.

Don't disappear, don't disappear! her thoughts yelled in hopes of it possibly hearing her pleas and her fingers just barely touched the white light around the fissure, until... Take me back home-- Almost like begging, her mental voice quietly spoke and felt the same pressure as before. Next, she went in, getting pulled in from the sudden suction almost instantly, and when she was gone-- It was only a matter of seconds until it faded away.

Through the crack and outside the other, within a blink of an eye, she appeared. High above an ocean near a city, the faint sound of her suitcases was heard falling just above her, and with nearly missing their handles she caught them. A sigh of relief left her as she fell, ignoring her flapping bun and the green ties holding it that whipped past her head.

The ocean? At the speed I'm falling, I don't think I'll be able to sprint across the water. Think-- think...! In her mind, a slight panic rose the closer she saw the water's surface become.

All around her, stars in the sky, the moon high and reflecting its rays on the horizon, there were no options for her to keep herself from falling. Alas, her suitcases were hugged close to her chest and her legs scrunched up. As soon as she splashed into the ocean, it took her a while to surface and when she did, a faint gasp for air came from her lips. Her green eyes locked onto the afar shore, she was lucky to even be close to it considering the distance she fell.

I wouldn't have been able to glide my way down, gliding is only done with short bursts of speed or when I'm free-falling somewhere high-- without anything in my hands. A sigh escaped as she floated there, Rin needed to get to the shore so she decided to try swimming. Feet kicking, one handle from a suitcase in her mouth, the feline did her best to breaststroke with one hand, and very slowly was it working.

It took her a long while, with the exception of a rock she managed to find under the water and pushed herself off of it to go faster. When she finally reached the sands, she was crawling her way out of the waves with one suitcase hanging from her mouth, and her free hand trying to keep herself balanced on her available three limbs.

Gradually the feline rose to her full height and took the case back into her hand. Gawking now, staring at the city lights far past the beach she stood on and pondered on what to do next. What do I do now? This place is so...different. This isn't the city I was in, Genos and everyone were supposed to meet up in city H but this... her monologue paused for a moment, and chose to take in more of her surroundings. Seashells, a small beach shack not too far from her, and a couple of old soda cans buried within the sands.

Nothing, there were no signs or answers where she stood. Her fists tightened slightly on the handles at the thought of being stuck in a place so unknown to her. The shack-- I need shelter or a place to hide so I can figure everything out. I need to get home, but where home is-- At this point, it's beyond me. Her feet sauntered across the sands towards the shack, dripping wet trails behind as she neared it and saw that it was hardly touched. A swinging closed sign hung loosely next to the wood door, which had a few rotted holes that many critters could crawl into.

Halting in place, her ears listened in closely for any signs of life inside and waited. No voices, no breaths of air, no dishes clanking, or even footfalls. After a few minutes, she concluded that no one was there, so now, her foot lightly pushed it open and made the door eerily creak. A simple thin mat was on the floor, an old bed, and an abandoned outhouse to the side of the shack were there. The smell of old wood and dust was enough to tell her that no one lived there.

After a few cautious steps inside, her slits roamed the shack, even though it looked abandoned it didn't mean it was safe to lower her guard and chill. I don't understand... Alright, I'll need to write a letter to Vei before the sun rises. Our stuff can sit in here for now. Not a single word was spoken, in her mind, she concluded and lifted the suitcases.

A shelf above the old bed could be seen and looked almost hidden, much to her luck, and decided that it was the best place for them. Her foot pressed against the bed so she could reach it and plopped both of them up there, in hopes of being hidden. There-- Now, the letter. Quickly she opened one of the cases, snatching a paper and pencil.

She used the wall to write on and explained everything that happened. From how she got sucked into the crack, to where she stood now. Not a single detail was left out, the feline didn't want any misunderstandings so she hoped Vei would be able to help find some answers.

After placing the pencil back into the case while closing the lid, her green eyes looked out through the small hole in the wall and saw the moon. It's still late, I'm guessing around twelve? So that means-- I might've been swimming for a couple of hours. I still have some time before sunrise, so I can go out and explore a little. I need to get as much information on this matter as possible, anything to help Vei out. With that, her silent steps barely made a creak in the floor when she went to leave.

A couple of moments later, a pair of white, fingerless gloved hands gripped the edge of the roof. Rin pulled herself up with her legs crouched and sat there for a moment to ponder on where to start. Where to look... The police are good for holding records of victims and other crimes, the library is good for storing and learning about history. Schools have documents for their students and teachers, but they do have science facilities. I might check there first, though not all schools have those. I might have to try somewhere else that has any kind of scientific information on what I just experienced. There were several options to think hard on, where to start looking, and a plan B, if the place she searched didn't have what she was looking for.

Sluggishly rising to her full height, within seconds the woman vanished and left behind an afterimage of herself that faded just as fast as it appeared. Through the streets, up the hills, and past vehicles that stopped at red lights, she ran. Only a blur of black and white with a tiny bit of green could be seen, as the feline zipped by a car.

Now, at a normal speed, she was; still rather fast to where only a blurred image of her person could be noticed, and raced past a man in a trench coat on the sidewalk. His blue eyes lit up with surprise when he nearly stumbled and saw the blurred image of her.

Rin skidded to a halt just barely and quickly scaled the apartment building she stood next to. Fingers suddenly digging into the stone, the feline raced up the side like a cat climbing a tree and jumped from a bar that linked the structure to another, to the rooftop. She needed a better view, something that would let her get a grasp on where she was at.

Her eyes viewed the vast city around her that was full of lights, and a large hill covered with trees could be seen in the far distance. Her slits thinned to improve her sight like a scope on a gun so she could see further out, allowing a better look at the forest. "Just a forest," her quiet, soft words left her half-masked lips and made her gaze return to normal. Those very slits looked down at the sleeping city in hopes of spotting a school nearby or some sort of laboratory. Sadly, though, she couldn't find one.

I need to know where a nearby school is. Preferably a high school or college, a school with higher grade knowledge of science. Swiftly her eyes scanned, trying to pick up any sort of place she could use as a plan B.

"Hey, you nearly pushed me out of the way earlier, so I couldn't help but notice you climbing this apartment when you did. What's the hurry, kitty?" A man's teasing and deep voice, questioned the feline from behind after she heard a few steps making clanks echo from the metal stairs to the side.

Rin's slits moved to her peripherals, not once did she stir from his approach. No levels of hostility, good-- I can ignore him then. I don't want anyone getting in my way. Mentally speaking, a hint of annoyance laced her words just before her eyes glued themselves back to the city.

"Hm? No answer? The silent type, I take it? Or are you just too scared to answer a stranger?" As soon as the blue-eyed shady man asked that, with a hint of mischief in his voice, his gaze widened at how fast she disappeared. An image of herself was left behind for but a second before it faded away and not a sound or a word was given, it unnerved him a little.

On all fours, like a feline, Rin sprinted and leaped from ledge to ledge across rooftops. Her attention was dead set on reaching a convenience store nearby that she spotted up on the apartment. As soon as she jumped across a dark alleyway to the next roof, her feet cat-walked alongside the thin concrete beams that stuck out from the edges of the building.

Her knees bending and her hands between her legs, very slowly she brushed them down the side of the beams to do a large hop to get to the roof of the store. Her palms touched the store's roof first before her feet and remained frozen in place for cautionary measures. Those eyes that gave a straight stare never faltered, not even a blink, before she stood and looked around. I can't go inside. With this being a store, people are bound to be roaming around collecting their groceries. her thoughts swarmed. She needed information and what better way than a place where people go often?

People always gossip... If I don't get any hints or clues from hearing other people's conversations, then I'll have to try somewhere else... again, her quiet monologue echoed. This time the feline chose to wait it out, so she gradually crouched to sit like a cat and shut her eyes calmingly; if she needed to wait, then she would. Patience was always one of her mental strengths, it helped her find openings, to hunt, to flee, and more.

In fact, with her eyes closed, her ears twitched to show that her attention was on all the sounds around her; focusing on that than her other senses, so she could pick up on conversations easier.

"Oh, come on!" A child was heard begging, as they left with their parent carrying groceries. "I won't break it!" They tried to reassure but all they received was an annoyed sigh and a grunt from what she could assume was the kid's father. However, that wasn't important enough for her to keep eavesdropping on.

Not much longer did a couple of giggling teenagers come walking towards the double doors of the store, conversing about quirks and the like. It interested the feline, her head perked up just slightly at the mention of students from a class called 1-A. "He was so cool! All of that ice, then the fire! It- It was like... WOOSH! Then the whole stage got covered in flames! U.A. Has some powerful students doesn't it?!" An overly excited girl laughed with so much energy in her voice, that it could be heard from a mile away.

"Yeah, he was great! That other boy too, the one with blonde hair, wow! Such a temper...but really strong explosives too!" Another girl yelled along with her friend as they went into the store, not caring if a little bell alerted the people inside about their entry.

When they entered and their voices muffled, Rin's gaze snapped open. U.A? Where's that at? Mentioning students-- U.A. Has to be a school right? So, what is this that they're calling quirks? The little bit of information she received only left more questions in her mind. Now, with her gaze looking up at the moon, she saw how much lower it was since the last time she checked it. It was almost reaching the horizon, so she had to hurry. Just a little bit longer, I don't have much time left. I guess I'll leave Vei to find out where this U.A. school is. I just hope her temper doesn't ruin anything. Those slits moved to look in the direction she came from, Rin knew that she had to go back to the shack and write a side note. Vei won't be happy. That was her last thought before fully standing.

Crouching once more, as soon as she jerked herself forward she vanished and left behind an image of herself, for only a millisecond. If she didn't let her and Vei's body sleep, they would both be equally exhausted later.