* Soulmate AU

* Jumps between the pairing

* I hoped the transitions are bearable

* Ending is based from an Audio Book

* Will be cross-posted on Archiveofourown (ao3) under the same name

* Contains moments of OOC

Saitama was five years old when it happened. His skin began to burn; the blood bubbling underneath. It felt as if someone was carving into the flesh, letters forming into deep, permanent scars. The boy screamed every moment; body thrashing and nails clawing at the bare skin. His body; which was still damp from his bath moments before heated, evaporating any droplet of water.

His mother; a beautiful woman with dark red hair and blue eyes was helpless to watch her son. Her husband; a tall, slim yet muscular man of thirty-two watched from the doorway, his face contorted into one of understanding and pain. The couple could do nothing for their child; it was a part of every person's life. They had gone through it themselves; the pain, the burning, the scarring and the tears. Experiencing it for oneself was different from watching it happen to one of your blood.

It had taken nearly five minutes; each word scripting itself onto his skin with his own blood. The writing wasn't large; it was just enough to be able to read. The surrounding skin was red and angry; every letter dripping with blood as the pained child panted in his mother's arms. His forehead was covered with sweat and his ribs ached. The child's heart was nearly audible; the effort it put in as the boy tried to regain his breath only caused the red liquid to trail down otherwise pale skin.

The mother shushed her child; soft, salty lips pressing into his forehead as her slim fingers carded through his black hair. The father was quietly moving around the cramped bathroom; a wet, warm and soapy cloth held in his hand. Blue eyes met brown over the boy's head; the mother nodded as the father knelt before the pair. Even as her child thrashed; the mother comforted him, arms trying to hold the boy in place as the father cleaned the new wound. A wave of pain for her miserable child overtook her; tears leaking once more from her lashes.

The soap and water stung the child; yet it soothed him moments after. The somewhat traumatized boy curled into his mother; arm gingerly held to his chest, careful not to touch the scarring words. With an incomprehensible mumble; the child fell asleep, mind and body exhausted as he became limp in her arms. Lovingly, the mother brushed back his back locks; uncaring if he was naked and covered in a sheen of sweat. "What does it say?" She asked; red-lined blue eyes locked on that of her sleeping child.

The father didn't respond; the air becoming thick with tension as he hesitated. His tanned and scarred hand lingered on the child's ribcage. Inches away from his fingertips laid his son's soulmate's first words to him. The man was overwhelmed with confusion and pain and anger. What kind of way of greeting was that?

The mother shifted; arms shaking a little from the effort of cradling her child as she sat down on the floor. She was uncaring if her clothes became soaked from the water on the tub and tile. The woman didn't press her husband to tell her; she knew that he was still trying to wrap his mind around what had just happened. Many people didn't get their words until they were older; at least eight or nine. A family friend had told the couple before that she hadn't gotten her words until she was nineteen.

Knowing your child had a soulmate; it lifted a weight from their shoulders. They wouldn't have to worry as much for what could happen to their child when they went. Despite this; watching your child go through this pain when he was so young, it crushed them. They never knew that it could leave them feeling like this; the relief of knowing their son wouldn't have to take the world on alone.

The father cleared his throat; the sound sudden in the otherwise nearly silent room. The only noise before having been the now steady of Saitama's breathing. His small hand curled on the mother's shirt; fingers clutching the material. "Hey, who brought a Class-B nobody along?" The father's voice was croaky and low. The mother could only blink in response; confusion muddling her mind as she looked to her spouse.

Seeing the man's nod; the woman looked down at her son, her head tilting in an effort to read it for herself. She read it once. Then again. The third time through; she was mouthing the words. They felt strange on her tongue; instead of making her feel better, it left a heavy weight in her stomach.

No matter which way she tried to think of it; these words didn't make sense. After telling her husband as much; the couple took their son to his bed. They worked together to dress him in a pair of pajama pants and carefully wrapped his new words. They took a few days to heal; and they bled a lot. After making sure he was asleep and warm and comfortable the parents left him with a softly spoken good night; closing the door slowly behind them.

Tatsumaki was eight years old when she felt pain like none she had experienced before. She fell to the ground with a scream; surprising the scientists and the workers around her. Vibrant green eyes filled with tears as she curled in on herself. Her skin seared with pain; almost like someone was trying to burn her. No one tried to help the child; many of them standing and watching as the words were etched onto her skin.

Murmurs went unheard by the screaming child; blood seeping into her clothes and dripping in red trails down her back. Five minutes after the start of it; the green-haired esper was left panting and sobbing on the ground. No one surrounded her now; one of them having felt enough pity for the young girl that he ushered the others away. Tatsumaki's left shoulder blade burned; her shirt having now become sticky and glued to her skin with the dried blood. Blinking away any lingering tears; the girl forced herself to stand.

Her legs shook with every step; her breath rushing out of her mouth as blood pounded in her ears. Her vision was blurry; but still, the child moved back towards her room. Once she made it to her bathroom, the girl took a deep breath; holding it as she let a green bubble of energy enshroud her. Using her psychic powers; the esper cut away her shirt, biting her lip as she felt the material tugging on her skin. Tears were leaking from her eyes when she managed to pull the ruined shirt away.

The esper barred an arm over her developing chest; her right hand reaching back to move curly green hair over her shoulder. Turning her back; the girl could barely make out the words amidst the scarring tissue and crusted blood. "Who is this…sassy lost child?" was etched into her skin. The child could feel tears welling in her eyes; not from any lingering pain but from disappointment. What kind of person did she have as a soulmate?

Saitama looked at his words all the time. The scars healed; the pain of it fading away into a memory. Now, they were script upon his skin, letting the twenty-two-year-old man know that out there; somewhere, someone was for him. Every day the man trained; he practically put himself through the wringer, having decided to jump into the deep end of muscle training and not allow himself a break. Unlike others; who often built up their endurance and let themselves rest one or two days a week, the man did not.

He wanted to be a hero; and to do so, he did one hundred push-ups, sit-ups, and crunches each along with a ten-kilometer run every single day. His muscles ached and his bones creaked; but he still did not give in. The man knew that if he had stopped; then he wouldn't be able to finish, and he couldn't let that happen. So, every day; the man woke up at six, worked through the sets then went out for his run. When there was a monster attack; which was becoming increasingly common, the man would go to help.

Often, he ended up bloodied and bruised, feeling worse than before. But he still grinned and bore through it. Saitama hoped that he could be able to protect whoever his soulmate was. Besides, becoming a hero was a childhood dream of his. So, he stuck by his regimen.

Tatsumaki felt bitter towards her soulmate's words. The twenty-five-year-old heroine often found herself; dressed down to her bra and panties in front of the mirror. Green eyes lingering on the messy scrawl; unable to look away even as her neck cramped from the prolonged position. She wanted to meet her soulmate; no matter what she told herself, or her younger sister, Fubuki that feeling remained true. But she was still filled with resentment.

The words were an ever-present reminder of her stature. The young female was short; and her body wasn't one to boast about. Instead, all of the assets had gone to her sister, who was younger by five years but often was mistaken to be the older of the two. The cocky esper couldn't keep a smirk from her lips as she thought of the painful ways the people were often made to realize their mistake. Though she was listed as a hero; the woman didn't take kindly to those who looked down on her.

She was strong; sometimes even said to be the strongest esper in their portion of the world. She was S-Class rank two; Tornado of Terror, damn it. The woman wasn't going to allow anyone to hold her back. Not even her soulmate. Even as she told herself; a smaller, quieter part of her whispered, hoping that the one meant for her would stand by her side.

Saitama was twenty-five when he his life changed. The now bald man had met Genos; a nineteen-year-old, angry cyborg. Despite the irritation the laidback hero for fun felt towards the younger male, he also felt sympathy. Something within him aching to help the male as he was asked to take the guy as a disciple. Saitama stopped; turning slightly to look back at the broken heap of metal.

Unashamed of the fact that the man was naked; he studied the teen briefly. He wanted to say no; he didn't have time for a student. But, instead of his throat working and lips moving to form what he thought; he found himself saying yes. The yellow eyes staring unwavering at him; even with the intensity, something lingered underneath. It was a deep-rooted pain.

A month passed for the pair; Genos, as Saitama was later reminded was slow to change. No matter how the older male went about it; the teen was still prone to acting first and asking questions later. Which is what often led the cyborg to be broken on the street and the bald man walking around; searching for as many pieces of him as he could find. A month and a half passed since their fateful meeting; when the elder was asked why he wasn't registered with the Hero Association. It had been a rough day for the man; having run into a purple and black-bodysuit-clad ninja and being painfully made aware that he was unknown.

In his anguish of this realization; the hero had been uncaring as the man proclaimed to be his rival and promising to kill him before leaving. Saitama was distracted as Genos rambled on and on before the mention of the Hero Association struck a chord within him. "If you take the test with me; I'll take you as my disciple." He told the teen; unaware of the confused look the cyborg gave him. Over the next few days; they prepared for the tests. Genos was overlooking the qualifications and rules while Saitama filled out his application and reading a manga.

The tests had been over quickly; the cyborg ranking into S-Class right off the bat while the bald, newly made professional hero was put into C-Class. Admittingly; the man was disappointed, thinking of how his soulmate would react if they knew of his standing. Would they care? He couldn't help but ask himself; even as he declined he offer of Genos going to talk, threaten really, the higher-ups. The pair had sparred and gone to eat udon. Saitama told Genos of the newbie-crushing when another hero had approached them.

Saitama was left at the table; mindlessly playing with his cooling food as he found himself thinking once more of his soulmate. Would they too be a hero? Or would they be a civilian? Would they be male or female? Older or younger than him?

The man could feel a pain in his chest; sharp and cutting but brief. Would they reject him? What would be the driving point? His unappealing and lackadaisical appearance? His hero work or the fact that he basically had no drive now?

He was too strong. He often found himself unable to empathize with others. The only time he felt emotions as he did before now were in moments he thought of his other half. But what if they didn't want him? What happened to others who had gone through that?

Saitama didn't want to find out.

Tatsumaki was twenty-eight-years old now. Feared among civilians, heroes and monsters alike. But the scarred woman found herself uncaring of it. So, what if she was said to be hot-headed and rash. People should just get to the point when talking to her; she was a very busy woman.

She didn't have time to deal with small fries. If it didn't cure her of her boredom at times; the esper found herself wanting to tear the Hero Association from its roots. The whole system was ridiculous and corrupt. The reward system was nothing more than a popularity contest; and the ranking committee often got a large head when overlooking the heroes. Even as she realized this; the heroine couldn't do anything about it.

Even if she threatened others; they wouldn't change. They'd just deem her as a threat to themselves and others. The best situation she would find herself in after that would be being out of a job and losing her standing among others. The worst-case scenario…well, the heroine didn't want to think about that. Humans were capable of becoming monsters if pushed far enough; that was shown practically every day.

Once more the heroine found herself before a mirror. Pale skin free of her dress; green hair placed over her right shoulder. The scars littering her back and stomach were unimportant; the esper only having eyes for the words on her shoulder blade. It was still saddening; disheartening to think of the person who she had been paired with. Her mind whirled with thoughts as she stared.

Would the person be a hero? Would they fear her? What were they like? Would they reject her once they realized who she was? The esper's stomach rolled as she was overcome with nausea.

Tears welled in her eyes as the woman fell to her knees. Her hand clamped over her mouth as the other cradled her stomach. Her shoulders began to shake as tears leaked from her eyes; the sad heroine uncaring of the sight she made in her own home. Nausea ebbed away as her sobbing was stifled to hiccups. Her tears dried; leaving tracks over her face.

Something weighed heavy in her stomach as her tongue was left with something bitter. Her shoulder blade pulsed steadily; a mixture of pain and comfort seemingly emitting from the source. The woman stayed on the floor for a moment longer before she picked herself up. Even though she was alone in her apartment; she refused to be seen as pitiful. The woman's head was held high as she walked away from the mirror.

Months had passed since Saitama and Genos had joined the Hero Association. Genos had gained standing among the ranks; the cyborg often could be seen in their shared apartment reading his fan letters, burning the creepier, over-the-top ones. Saitama wasn't as popular as the teen. He too, received letters. But it was more hate mail than anything else.

The bald hero was marked as a cheat and a fraud by civilians; the floodgates for these remarks having been opened by a pair of jealous and greedy heroes in a previous situation. But Saitama didn't truly care; at least that's what he told himself. Despite his constant remarks that people had a ton of time on their hands. He couldn't help but wonder if one of these were from his soulmate. The thought alone made the man feel sick; and pushing whichever task he was doing away.

Whenever he was stuck on this train of thought; the man would leave the apartment and go look for a monster. Sometimes he found one; other times he didn't. The man was gone longer when he couldn't; the emotion taking longer to squash down. When Saitama came back to the apartment; Genos often looked at him with a sad, understanding look in his yellow eyes. It was a strange emotion the man felt when he saw the look; it rankled against his nerves but comforted the hero at the same time.

The day that Tatsumaki had met her soulmate had started out terribly. The heroine had woken up with a throbbing headache; and she felt sleep-deprived, having been unable to rest soundly the night before. If that wasn't bad enough; she had been made to skip breakfast, as she had received an urgent call from the Hero Association. Dragged out into the middle of some mountain range; she had taken care of a monster dubbed as The Ancient King. But, instead of letting her do her work in peace; as soon as she was about to start, the esper had received another call, asking her to come to headquarters.

After arriving; she had been given no information to why she was called, simply told that everything would be explained later. Two hours, she was forced to wait for the others to arrive. The heroine had been standing out in the hallway; taking a moment to try to calm herself, when it happened. "No handshakes, I acknowledge only the strong." She could hear Atomic Samurai; her curiosity peaking as he continued. "Once you've climbed up to Class-S, I'll greet you properly." Tatsumaki couldn't help but draw closer to the voices; her curiousness overcoming her want to stay out of sight.

The heroine saw Silver Fang first; one of the only heroes she truly respected. Then; she saw the newest ranked S-Class hero Genos, but what really drew her eye was the flash of light off of something reflective. Her green eyes lingered on the man; drinking in the sight of him. He was muscular, even the ill-fitting hero suit he wore couldn't hide that. His head was round and face inexpressive; not a single piece of hair was on his head.

Though he looked young; the man was bald. Did he shave his head? Or was it the genes? She asked herself before she focused on him once more. The esper studied the man intently; something tickled at the edges of her senses, but she couldn't make sense of it.

Something inside of the heroine shifted when their eyes met; dull, brown eyes meeting vibrant green. The heroine could feel her heart stutter; her face filling with blood as she blushed under his gaze. Tatsumaki shook away the feeling; her frayed nerves and bad mood worsening as she finally snapped. "Hey, who brought this Class-B nobody along?" The woman said without thinking; beginning to rant before any of them could respond.

She didn't see the hurt flash in brown eyes.

Saitama could only feel pain; heavy on his chest, his throat tightening as he heard the words. The words which he grew up with; he accepted the hurtful phrase. He knew what the person, what she was going to say. But it hurt; more than he thought it would've. The hero could feel his head swim with the realization; the pain of it overwhelming him.

He didn't see the confused and concerned looks the heroes on either side of him give. Saitama didn't know of the darting yellow eyes between him and the green-haired heroine. "Who is this…sassy lost child?" Saitama barely heard himself ask; chest throbbing as the words came out without a thought, his words sounded dejected even to him. His head was bowed slightly; eyes staring blankly at the floor as he listened Genos ramble. Saitama pushed forward; away from the elderly hero and his disciple, away from his soulmate.

He didn't see the shocked expression come over the woman's face, pain filling her green eyes as her voice fell silent.

Tatsumaki was left in the hallway stunned. Her angry words crumbling as she saw her soulmate react. His previously blank expression being replaced with one of dejection. The heroine could feel bile rise in her throat; heart clenching as her stomach filled with something bitter. The moment the words had slipped past his lips; she knew.

He was the one meant for her.

This realization left the woman feeling angry and saddened. She was angry with herself. Angry with the hero association and even angry with him. In one moment, her life had been flipped upside down; all because of one dejected look on a man she didn't even know the name of. Tatsumaki shook her head; green energy wane around her figure as she floated into the meeting room.

The heroine was unaware of the odd looks she received. Uncaring if a pair of yellow eyes glared holes into her. She plopped herself into her usual chair, green eyes blank as they stared at her lap. She ignored Silver Fang's attempts to talk to her; green, curly hair acting as a curtain around her face. Tatsumaki could feel her skin crawl and buzz; the proximity from her soulmate electrified her, an odd mixture of comfort and pain heavy between them.

Tatsumaki let herself look through her hair at the man; her heart stuttering as she saw him. He sat dejectedly in his chair; almost acting as a mirror to her. Red glove-clad hands held a scalding cup of tea, but he didn't drink from it. Instead, he stared desolately into the liquid; he too, ignoring his neighbor like she ignored hers. The heroine was left with a sour feeling as she looked to him; her mind whirling as she tried to make sense of everything.

Could she fix what she had done?

Saitama came out of the ship with one punch. Brown eyes dull and flat as he was met with the open space instead of another hallway identical to the one before it. "Oh, I'm out." He said to himself; a tiny, nearly unnoticeable smile coming to his face for the briefest of moments. Out of the corner of his eye; the hero saw a small figure clad in black and enshrouded with green. "Hey." A voice said; distinctly feminine and cautious.

"Can I talk to you?" The heroine asked as Saitama looked to the source of the voice. His stomach rolled uneasily at the sight of his soulmate. The pain and hurt from before opening once more when he saw her. Saitama wanted to say no; some part of him wanted to reject her like she had seemed to do for him. But like the moment with Genos; his mind and his heart weren't aligned in reasoning and he found himself saying yes.

After being led away from the ship; some distance away from everyone else, the heroine started to speak. "I'm sorry for before." She started, voice soft still and green eyes directed to the ground. The woman held herself level with him. Her figure was a foot or so from the rubble; body wrapped in green. Saitama guessed it had something to do with her power.

"-can we meet up sometime?" Her voice broke through his thoughts; making the man blink. Saitama looked over the woman once; her body language dejected and folded in on itself. Something inside of Saitama twisted at the sight; pain filling his chest before he answered. "Sure. I'd like that." He said; surprising himself to find that he meant it. The hurt was washed away as the woman beamed in response.

"I'm Tatsumaki." The heroine introduced herself suddenly; her face flushed as she realized the man didn't know her name. "I'm Saitama." He said in response; brown eyes flicking down to look at her as his lips pushed up to a small, amused smile. It was their first date; a month or so after the attack from the Dark Matter Thieves. It was also the first time they've been able to talk freely with each other. Things had been a bit rough at first.

Their meeting after the attack hadn't gone as planned. Neither having forgotten the way they first interacted. The pain still fresh on their minds even a week later. The conversation had been stilted and strange. Rather uncomfortable, actually.

The second meeting had gone better; but not by much. They were able to talk at least; exchanging information about themselves, like favorite colors or snacks. There were still some rough patches between them; a lag in the conversation falling into awkward silence. It hadn't occurred to them that they didn't exchange names.

It was the third time that they met up that she actually met Genos outside of the Hero Association. The heroes hadn't meant to run into each other; instead, they had all intended to fight a Dragon-Level threat monster. Let's just say the bald had beaten the others to it. The interaction between esper and cyborg had been stilted and uncomfortable in the extreme. He hadn't forgotten the way she had left his sensei feeling that fateful day.

Tatsumaki hadn't stayed long after that was brought up.

Some meetings after that were hit and miss. The heroine hadn't been sure that they were really making progress. Until Saitama; not meeting her eyes or even looking at her, casually asked her out. His hand felt warm in hers; but a little sweaty too as she reeled from what he said. Tatsumaki couldn't forget the relieved, happy expression he gave her as she agreed.

Here they were now; walking around the summer festival in City-Z. The pair content to walk through the grounds instead of going on rides. Each of them ignored the surprised looks civilians gave them; their murmurs falling on deaf ears as they just relished in each other's company. Something dark and gloomy caught the esper's eye; making her draw them to a stop. It was a haunted house.

"I had a part-time job here." Saitama said; making the esper look to him. His face was as blank as ever. But the heroine could just barely see the faint smile on his lips. "There was this one chick," He continued; brown eyes filled with mirth and reminiscence as they stayed on the display. "she thought I was a ghost. Started talking about powers, it was hilarious." Saitama finished; unaware of the widening eyes of his soulmate.

"That was you?!" Tatsumaki screeched; face flushed in anger and embarrassment as she remembered that moment in her life. Her power darkened around her frame as she squeezed his hand. "Damn it, baldy; you scared me!" The embarrassed esper continued to yell; completely unaware of the shocked then understanding look Saitama gave her. Tatsumaki was absentmindedly rambling now; eyes unfocused as she talked. The heroine froze as she felt something brush her hair.

Saitama was bent over her; one hand carding through her green hair soothingly, lips pressed to the strands. "I'm sorry." He apologized; his simple words filled with such sincerity that any negative emotions she felt drained away. The flush of blood wasn't one of anger now but pleased embarrassment. She couldn't believe that he had just done that. "It's fine." The heroine said quietly; cheeks pink as she felt comforted just by the small kiss.

Maybe things would be good between them after all.

Disclaimer: I do not own One Punch Man or its Characters. The Author and Creator do.

Author's Note: Hi everyone, I hope you enjoyed the story. I know I have other stories to do; but I really wanted to try this one. I had been reading a bunch of soulmate au's that I just had to try my hand at it. I hope everyone enjoyed it. It was really fun to write.

If you think I should've done something different; please tell me. I appreciate constructive criticism.

* The ending I had made from Summer Festival with Tatsumaki