Dragons and Heroes: The Fist Marks

Alright, folks! Here's the side project that I've been working on. Basically another side of the Legacy story that I write for the fun of it, just as the summary said. Enjoy! R&R.

Disclaimer: I do not own High-school DxD nor One-Punch Man.

Special thanks for KoroshiyaBlaze for being this story's beta-reader!

Chapter 1: The Hero and The Magical Girl

The Underworld...

A place in religion and mythology where the souls of the departed shall go to. It is also to be believed as the place where malevolent beings and creatures reside in. Some people also believed that it was the home of fallen angels who had been banished from Heaven as well. The Underworld is roughly the same size as the human world but with a much larger landmass, as there are no oceans. The sky is originally purple during both the day and night, however the current Four Great Satans adjusted the flow of time to match it in the human world for the sake of the reincarnated devils. They reproduced a false moon using magic and made the night's darkness the same with the human world's. In addition, the underworld itself was split into two territories: the devil's territory and fallen angel's territory.

In the capital city of Lilith, there was a parliament building where the devil kings and other government officials worked on managing the underworld. The building sometimes was used as an alternative housing, complete with bathrooms and bedrooms for those who had to work overtime. Currently in one of the guest rooms, there were two people sat in front of large, flat‐screen television. On the television screen was a show depicting a girl with pink frilly dress swinging something akin to a magical wand around, before switching the scene that was showing what was called, 'Miracle L evia‐tan'.

After the show had ended, one of the occupants of the room, Sirzechs Lucifer, turned from his seat towards his companion, a bald man wearing a set of charcoal grey suit with yellow tie.

"So, Saitama‐kun. What do you think?"

Taking another bite from the snack that had been served to him beforehand, Saitama only raised his eyebrows nonchalantly. "When you said something like 'last, but not least', I didn't expect something like this." Saitama pointed his thumb at the television screen with somewhat disappointed tone. "Honestly, I prefer when you took me to that floating island and that place with lots of organic products earlier."

Sirzechs hummed thoughtfully before replying. "Sorry if you don't like it, Saitama‐kun... I actually kind of ran out of place to show you, and I decided to show you underworld's most favourite TV show. I thought you might like it."

"Well, I appreciate the thought..." Saitama felt a little bad at Sirzechs' apology. "Not that I don't like it, but... It's just not my thing." Saitama explained. " Though, I know someone who'd love this show..." Saitama's thought trailed to a certain man with scars on his face. "And do I really have to put this on?" Saitama tugged his collar a bit, the man always felt a bit suffocated with the tie and all.

"I'm sorry about that, but I can't set up a bad example in this place. You can at least loosen up the tie, though." Sirzechs excused, which Saitama complied as the latter loosen the knot on his yellow tie.

The reason Saitama was in the underworld in the first place was for sightseeing. Not long after Saitama's 'little spar' with Sirzechs at Gobi desert, which involved some old monkey suddenly appearing on top of a green dragon and complaining about the former two destroying a good part of the monkey's homeland, Sirzechs became rather fond of Saitama and later invited him to explore the underworld, particularly the devil's territory with the devil king himself as a guide. Sirzechs himself also planned to introduce his fellow Satans to his new mortal friend.

Saitama later found himself transferred instantly together with Sirzechs, which the latter saying it would be a one‐time special service only. They visited many places in the underworld, which was completely different from Saitama's expectations. The man expected wandering souls in the air, fiery volcanoes, sea of flames, brimstone or perhaps some cries and wails of despair of agony when he reached what was called as 'Hell', yet Saitama found something completely similar with the human world he came from, minus the purple sky and the lack of ocean.

Travelling from place to place, Saitama would be lying if he was not fascinated by the underworld. While Saitama is no expert in science stuff, Saitama admitted that the sight of the city of Agreas, complete with its advanced technology than the human world, had been breathtaking. Saitama could tell that people like Genos, Metal Knight and the brainiac of a kid from Hero Assocation would love to explore the city if they were given the opportunity. The man also enjoyed at the agricultural display at Auros, Saitama even making a mental note to himself to get some of their products to be delivered to his house as a souvenir to his new family.

And here he was now, watching the underworld's popular TV show that featured, as Sirzechs had informed, one of the devil kings who was in charge of the foreign affairs. Saitama was brought to the parliament building as it was time for Sirzechs to have his usual get‐together and lunch with the other devil kings, and it was a perfect opportunity to introduce Saitama to the other Satan as well. The two proceeded to move out from their current room to the dining hall where Sirzechs would meet the other devil kings.

"Ah, Sirzechs. I need to use the bathroom. Where is it again?" Saitama said soon after the two left the room.

"Go straight to that corner and turn right. The bathroom is the first door on your left. Sorry, but I need to be there first. Just go straight to the other end of this hallway if you want to catch up, okay?" Sirzechs pointed at the direction.

Saitama only nodded before turned on his heels. "It's fine. I'll see you later."

After trekking his way and passing several staff members, which fortunately had been informed about the human being the Lucifer's personal guest so they did not give another glance at the man, Saitama finally arrived at his intended destination. Looking back at the building itself when Saitama came in with Sirzechs, the former imagined that the bathroom alone might be as big as his house in the human world. Shrugging off the thoughts, Saitama immediately grabbed the handle and pulled the door open, which was actually locked and Saitama accidentally pulled the entire door off its hinges.

"Ah, crap. I broke it..."

Why the bathroom door was locked in the first place? Obviously, the bathroom was being used. The bathroom itself was not exactly a toilet, but it was a bathroom complete with a toilet and a shower to accommodate the members that had to stay overnight due to workload. Thus, when Saitama (forcefully) opened the door, his eyes landed upon the figure who was using the bathroom at that very moment.

Meanwhile, when Sirzechs was about to reach the dining hall where his colleagues/friends were supposed to be waiting for him, he suddenly heard a familiar shriek, along with a sound of a roaring explosion.

Serafall Leviathan is a devil king (queen?) who had a great self‐esteem. Born from the prestigious Sitri clan by the name Serafall Sitri, she flawlessly mastered her family's devil arts and soon inherited the position as the family head. Her mastery over ice and water made her became famous during the course of the Great War between Three Factions. Additionally, during the devil's civil war, Serafall joined the side of Anti‐Satan Faction and her power ability gave a great contribution to overturn the Old Satan Faction. Soon, she attained the throne of devil kings, receiving the title of the Prince of Envy itself and had been serving the underworld as one of the new Satans with the her comrades who inherited the other three of the original devil king's title.

However, over the course of her life, she became helplessly fascinated with the concept of Magical Girl, along with their mottos about love, peace, friendship etc. She decided that she would become a Magical Girl herself and make her own franchise, in order to teach the children about the wonders of Magical Girls, much to most of people's chagrin and disagreement (in the end, nobody truly dared to openly stand up against the strongest female in underworld).

Her career as a Magical Girl, in addition of her cute and cheerful personality, resulted her to have her own franchise to be the underworld's number 1 favourite among the populace. She also had made a good start once she planned to introduce her franchise further to the human world. She had gone through photo‐shoots, wearing skimpy, revealing outfit like mini‐skirts, stockings, swimsuits and even lingerie for the whole world to see, and she wasn't bothered in the slightest. In fact, it only made her proud of her own body.

However, the thought of someone seeing her entire nude body never once crossed her mind. She was proud of her own body, but she never imagined anyone to see herself in her birthday suit (with an exception of her little sister. In fact, Serafall sometimes wished that she and her sister could cuddle each other naked someday). She did not put much thought about it as she believed that she would only laugh it off playfully if anyone comes across to see her nude form.

However on that day, she had been proven how wrong she was.

It was another day when Serafall just finished the shooting of her latest episode of 'Miracle L evia‐tan', and she proceeded to take a quick shower before meeting her fellow Satan in the parliament building. Suddenly, when she was busy drying her hair, the door of the bathroom suddenly busted as someone pulled the door off of its hinges, allowing whoever it was to see her child‐like, yet glorious body. The person who broke the door was a bald man with somewhat irritating plain face wearing a charcoal grey suit.

The man, Saitama only blinked several times at the sight of naked Serafall, whom only frozen in spot in return. "Oh, um... Sorry, I don't know that the bathroom is in use..." Saitama rubbed his head awkwardly. "And I'm also sorry about the door. I'll fix it somehow." The bald hero narrowed his eyes slightly when he got a better look at Serafall, whose face was getting redder and fuming by seconds.

"Hey, aren't you the girl from TV?" Thus, not expecting the current situation at hand, Serafall Leviathan did what most women would have done at the moment.

"KYAAAAAAAAAAAAAHH!"

Saitama was taken aback at how loud the girl's scream was. Now that he remembered where they were, he quickly attempted to placate the panic woman before him. "Oh, right! The door! I'm sorry!" Saitama quickly stepped back and tried to put the door back to its position.

"Get the hell out, you perveeeert!" Serafall suddenly threw her own demonic energy in a fit of rage and embarrassment. Never had she imagined how embarrassing it felt to be seen naked by a random person, a man to add. Her demonic power flew towards Saitama, who quickly used the door as a shield in reflex, before the door was immediately frozen and was destroyed, becoming shards of ice.

PRANG!

"Don't look! Stop looking at me, you leech!" Serafall kept firing her demonic power as she tried to cover her modesty. One of her shots made a hit on Saitama and her power immediately froze, encasing a good part of Saitama's body in a large ice‐block.

At this point, people around had already made few distances themselves, seeking for safety from their rampaging Satan as they pitied the poor man that tasted the power of the Leviathan first‐handed. However, much to the spectator's surprise, the man simply broke the ice encasing his limbs through sheer brute strength. Every time the Leviathan's attack managed to froze a part of his body, the man would simply and literally broke the ice off his body while he tried to placate the enraged and embarrassed woman. The process had already happened for several times now.

"I said I'm sorry, but you already destroyed the door! Hey! Stop it! It's freezing, y'know! What's your deal about being seen nude, anyway? It's not like it turns me on or anything!" Saitama yelled back as he kept taking the brunt of Serafall's attack like it was just a nuisance. At his words, however, Serafall just felt her pride being insulted in even more ways than one.

Thankfully, just when Saitama finally got away from Serafall's line of sight, allowing the latter to compose herself and put on her set of clothes, Sirzechs and other noble‐looking individual had come running to the scene.

"What in blazes...?" Sirzechs muttered at the sight of the ruined and frozen state of the hallway, before he turned to Saitama who walked towards them. "Saitama‐kun, what happened?"

Saitama looked around awkwardly, looking for correct words to explain the whole situation. "Well... I... accidentally broke the door and I ran to the girl we saw on the TV earlier." The man pointed his thumb at the direction of the bathroom.

Sirzechs furrowed his eyes slightly before he finally saw a girl with twin‐tailed hair come out from the bathroom with a set of dark‐green shirt and long skirt. "Serafall?"

"Sirzech‐chan~!" The teary‐eyed and flustered Serafall whined at her fellow Satan as she ran towards him. "There's a pervert peeping on me! What do I do? I can't be a bride anymore!" Then her eyes landed on Saitama. "Ah, that's him!"

The woman pointed accusingly at Saitama, who was still lost of what exactly was going on.

(Scene Break)

As the Four Great Satans and single human were seated in the dining room, the situation could only be described as awkward and hostile, especially between Saitama and Serafall. Ever since the introduction between Saitama with Serafall Leviathan, Ajuka Beelzebub and Falbium Asmodeus, the female in the room had been glaring daggers at Saitama. If looks could kill and Saitama was more vulnerable, the man would've died hundred times over already. Falbium, renowned for his lazy attitude, could not help but curious as he raised his eyebrows at Sirzechs, who gave a bitter smile in return with a shake of his head.

Saitama finally could not stand the awkward atmosphere any longer and decided to do something to 'atone' his mistakes. "Um... I'm so sorry about earlier."

Serafall only huffed and averted her gaze away from Saitama and she grumpily focused on her meal. This left the other occupants to sweat‐drop at Serafall's uncharacteristic behaviour.

"Hahaha... Please cut him some slack, Serafall... Accidents do happen. I'm sure he didn't mean anything bad back there. Right, Saitama‐kun?" Sirzechs attempted to lighten up the mood as Saitama nodded in agreement.

"But Sirzechs‐chan~!" Serafall cried out, tears forming in her eyes. "I swear that his eyes were raping me back there!" Saitama narrowed his eyes incredulously at the statement. "And I've been preserving my body for So‐tan alone!"

Saitama furrowed his eyebrows at the strange name that caught in his ears.

"...So-tan?"

"You're going too far now, Serafall." Ajuka decided to join in placating the Leviathan. "Our guest here has apologized for whatever he's done to you, not to mention that it wasn't intentional. Shouldn't you show some mercy as a leader to overlook his mistake just this once?"

Serafall turned her glare at Ajuka, when their eyes met for few seconds, before glancing towards Sirzechs again, who also returned the look with hopeful and demanding stares of his own. The Leviathan also noticed that Falbium also gave her an expression that said, 'get over it already'. Finally, she turned back to Saitama, who still stared at her with his usual plain expression.

Few moments later, Serafall finally sighed in defeat. "...Fine, I'll let you go just this once... But don't think you'll get away so easily if it happens again, you hear me?!" Serafall pointed her finger at the man, who nodded furiously.

Suddenly, as if the incident at the hallway never happened, Serafall's expression started to brighten up in a blink of an eye. "So, why don't you tell us how you met with Sirzech‐chan here, Saitama‐chan~?"

Saitama blinked in confusion at the sudden mood swings from the Leviathan, as well as at the suffix used at his name. " ... ' -chan'?" The man threw a questioning look at Sirzechs and the others respectively, which was only replied with sheepish smiles, sighs and the looks that said, 'just get along with her.'

Saitama scratched his cheek as he thought where to start. "...Well, I happened to meet him somewhere in China. He was taking a break from his work if I'm not mistaken."

The others sent playful looks as they were aware what 'Sirzechs taking a break' actually was. The Crimson Satan himself only averted his gaze away while giving an awkward smile.

Of course, Saitama and Sirzechs had agreed beforehand not to mention anything about their fight back then in order not to cause an uproar. Saitama himself also understood that Sirzechs had an image that had to be maintained.

As the conversation went on, Ajuka asked, "Then, what were you doing for living before you meet Sirzechs, Saitama?"

Saitama remained silent for a moment. With everything that had occurred to him ever since he had arrived to this dimension, could he still call himself what he used to be? But after one thing lead to another, Saitama had found himself doing the things he usually did. Old habits were truly hard to stop.

"...A hero for fun."

"...What?" That was the only dry‐toned reply that came out from Serafall's mouth. The other Satan simply raised their eyebrows in slight surprises. "What do you mean by 'a hero for fun'? I never heard such... a funny motive before...?" Even the Leviathan was not sure how to respond.

"Just as it says. I used to work as a hero because I found it fun... It's like a hobby." "Okay. Not only did that sound kind of half‐hearted, I don't think you can say that being a 'hero' is a real job." Serafall retorted.

"Well where I came from, we're... kind of paid for being heroes. There's even an association for that." Truth to be told, only Sirzechs so far who knew about Saitama being from 'another world' and Saitama, honestly was too lazy to explain everything all over again.

"Really? I see... Then I should go check this Hero Association of yours out during my next visit..." Serafall mused, thinking that her career as a magical girl would take another step forward.

Inwardly grateful that no further questions were asked, Saitama himself felt that he needed to stop Serafall, but found himself reluctant in the end. " Oh well... It's not like anything bad is gonna happen."

And the lunch break went on without any major incidents.

Days passed and people in the Underworld kept doing their daily activities peacefully despite the fragile cease‐fire with the angels and fallen ones. Serafall Leviathan slumped on her desk as she finally finished the last sheet of her paper work. Letting out a breath, she then turned on her smart‐phone (invented and given by Ajuka Beelzebub for her social life) to see if there was any news regarding her territory, the Underworld itself, etc.

Rummaging through webpages, blogs and some other reports, Serafall found an update that there was a sighting of an S‐class stray devil in one of her more remote territories. The stray devil was formerly a queen and had been on the run for quite sometime now. Usually, this kind of issue would be dealt either by Behemoth, local guards, or middle and high‐class devils nearby, however seeing that she had nothing to do at the moment, she decided to stretch her limbs for a bit to deal with the issue herself. Not only the Stray Devil could be dispatched more easily by her power as a Satan, but if she went out there with her Magical Girl get‐up, it could promote her image as Miracle Levia‐tan in the eyes of populace who had not heard of her.

In other words, two birds with one stone.

Thus, Serafall Leviathan quickly changed into her 'uniform' and set to teleport straight away to her designated target.

(Scene Break)

Lo and behold, the moment she arrived at her destination, Serafall immediately noticed the uproar not far from her position. Usually, Stray Devils tend to use human world as their hiding place. That world's awareness of supernatural was almost non‐existent, safe for those who were deemed to be more 'special'.

After all, there would be only a few among hundred who would believe that monsters were lurking around the darkness and prey on human flesh, thus the human world served as the perfect hiding place for strays. There was a reason why Stray Devils would tend to feed on humans. Apparently, human flesh and blood contained some essence and 'nutrition' that could boost the stray devil's power if the devil were to eat accordingly. For them, humans are easy, nutritious meals. However, some stray devils were willing to take a risk by hiding in the underworld and prey upon their own kind because unlike mere weak humans, one devil possessed greater essence that might be on par with tens and hundreds of humans. The security in the Underworld was far more fortified compared with human world, but it was worth the risk if the stray devil could gain power much faster.

Ignoring while inwardly appreciating some looks from the locals, Serafall flew towards the spike of demonic power and found the local guards were surrounding a monster that resembled, or to be more precise, had mutated into something akin to a deformed human that had fused with a giant worm. It seemed that devouring fellow devils had made the stray's appearance even more grotesque than those who lurked in the human world. Serafall also caught that the monster seemed to be able to spit acid wide enough to cover all of its blind spots, preventing the guards to get close. What made things slightly more complicated was that there were still some civilians with children in tow, still being evacuated, and the stray devil made the evacuation much harder.

When the evacuation process was almost done, the stray devil released an earth‐based magic attack as the ground before it rose into an avalanche, assaulting the guard that was occupied on evacuating the rest of the children. That was when Serafall quickly made her entrance.

The devil guards and the civilians were about to brace themselves at the incoming avalanches, only to find the said avalanches were frozen, creating a large wall of ice, blocking between the now shocked stray devil and the others. Noticing that particular attack and sensing the overwhelming aura descending upon them, everyone looked up at the sky to see a woman in pink frilly outfit was flying with her 'magic wand' outstretched.

"L‐Leviathan‐sama!" one of the guards recognized the figure.

"Yep~! Bringing forth love and peace to all those who believe! Bringing the downfall of evil with the power of hope and friendship! Magical girl Levia‐tan has entered the stage~!" Serafall announced her presence with her signature move and pose with magical hearts somewhat appeared around her when she winked in the end.

One of the guards would like to retort his leader about the situation, however, one of his comrades, presumably his senior simply placed his arms on his shoulder and shook his head, as if to say that there was nothing they could do now. The guard who wanted to retort earlier only glanced at his comrades before he turned to look at Serafall again and he reluctantly retreated.

"Leviathan‐sama..." another one of the guards spoke in grief tone. "Forgive us, but the stray had swallowed several civilians and soldiers before you've arrived..."

Serafall, who was still facing the stray, only jerked her head slightly at the news, her expression was not visible by those behind her. But the stray saw the Leviathan's expression went to a complete opposite of her cheerful presentation she showed earlier. The monster felt as if its spine was frozen many times over.

"I see..." Then Serafall turned to the guard with a kind smile on her face. "Thanks for your hard work~! Just take everyone else away from here and leave the rest to me~!"

"Yes! Please be careful." The guard said gratefully as he wished his leader good luck before he joined the others to retreat.

It was one on one between Serafall and the stray devil now. Despite the grave news, it would not be difficult for Serafall to kill the stray in matter of seconds, not to mention that the word 'swallow' and the size of the monster's jaw gave Serafall another idea. The possibility that those who were 'swallowed' might still be able to be saved if the Leviathan could just kill the stray and cut its belly open to salvage the 'eaten' locals. It might've been an absurd way of thinking, but even someone like Serafall could always hope and dream from time to time.

The other devils who had gained safe distance, waited in anticipation to see Serafall Leviathan, the Magical Girl Levia‐tan in action up close.

That is, until one of them noticed something descending from the sky.

"Now, it's between you and me now, with the power of love, I shall punish you~!" Serafall announced with another pose, not realizing the incoming object.

The stray devil, who also did not notice something was descending right from above, knew well that its fate had been sealed at the moment the Satan herself arrived at the scene. The stray was still not strong enough to even fight back and it was completely futile to run away, so the stray decided to go down in a blaze of glory with one, ear‐splitting, defiant roar. "GRRO‐!"

BLAAR! SPLAT!

The stray devil's roar, its final fight, and ultimately its life were cut‐short as something slammed onto it, resulting its body to explode in a burst of blood, guts and innards. Unfortunately, Serafall who was positioned right in front of the stray took the brunt of the burst as her body was covered with white and green slimy substance, her eyes were closed right in time to prevent any of the dirt to get into her eyes with her nose cringed in disgust at the sheer smell enveloping her body from head to toe. When Serafall finally opened her eyes and realized the state of her body, no words were able to describe how disgusted she felt.

When her view, as well as everyone else's, cleared up, something was seen moving from the middle of what remains of the stray devil.

It was a person. A bald man clad in a yellow suit with red gloves and boots, finishing off with a white cape waving on behind his back. The man was busy checking what appeared to be the civilians that miraculously were still in one piece despite had been swallowed by the stray devil before. As the man carefully cradled a little girl in his arms, the man gently patted her cheek, looking for any signs of life.

"Hey, you alive there?"

There was silence for few seconds, few nudging later, the child in Saitama's arms began to flinch and her eyebrows were twitching. Soon the girl's eyes were blinking and she coughed a bit, trying to regain her breathing.

"Uh... W‐where am I...? What happened...?" The girl drowsily muttered her wonder. Her eyes slowly made out Saitama's rather silly appearance.

"Hmm... Good, you're okay." Saitama then stood up and slowly placed the girl down before he helped her to stand on her legs. Soon the others who were once inside the stray's belly also began to regain consciousness.

It only a matter of seconds until everybody started to cheer on Saitama.

"Woooow! He saved us! That... bald dude in cape, he beat that monster in one attack!"

"He saved us! He saved us all!"

"Thank you! We'll never forget about this favour!"

And the cheers went on, leaving Serafall remained standing, while still posing with her body covered in goo. One could say that Serafall was more like a very dirty statue that had not been treated for years. Saitama then noticed the girl covered in goo and blinked at the sight and his nose slightly cringed at the smell coming from her. "Err... Are you alright, there?" Saitama asked as he approached.

"L‐Leviathan‐sama...?" One of the guards hesitantly addressed his leader, still actually bothered about the smell.

Serafall simply wiped some dirt off her face as her body slowly trembled in disgust. Saitama's eyes widened slightly in comprehension when he got a better look on her face. "Wait a second, you're the girl from the TV!" Saitama commented nonchalantly.

Serafall did not say anything more as she immediately teleported away from the scene. The guards shouted her name but there was nothing else they could do to somewhat appease her. Soon the populace started to gather to applaud and thank Saitama for coming to their rescue and the man himself awkwardly tried to address each of the people's gratitude towards him until he managed to slip away and go about his way.

In the luxurious bathroom of a large mansion, which was one of Serafall's many homes, the Leviathan was busy rubbing the grim off her body under showers of warm water.

"Stupid baldy... 'Hero for fun', he says... Making a fool out of me..." Serafall muttered as few tears slipped from her eyes, hidden away under the rinse of water.

Those tears were... Well, it was not that Serafall was unhappy about the whole fiasco earlier. The Leviathan was truly happy that her people were safe and she inwardly was thankful for Saitama. However, a part of her heart thought, " Could he have done it like, more...'cleanly', maybe?"

Stealing her thunder during the fight was one thing, as much as Serafall dislike about it, but making her look like a third wheel which felt embarrassing as hell (or heaven?), creating such a mess like she was dealing right now, and not to mention the way he addressed her just... Pissed her off for some reasons. It felt as if she were watching Gabriel posing as another Magical Girl and plagiarizing her show.

As much as she was delighted about the safety of her people, her pride as a magical girl, whose duty is to protect and share the concept of love and friendship to populace, would not allow it. Turning off the water, Serafall took a deep breath and her eyes were set of what she was going to do.

She wanted to make peace between herself and her current situation.

Ajuka Beelzebub was... confused, for the lack of better word. Currently, he was in on a yacht belonged to Sirzech with the Lucifer himself was standing next to the Beelzebub on the docks. The yacht itself was distanced quite far away from a small, inhabited island, surrounded with protective barrier on the Arctic ocean.

"...Mind to remind me why we are here.. Again?" Ajuka asked as he held down a sigh.

"...Well, someone has to keep an eye on those two." Sirzechs nonchalantly replied. "And two pairs of eyes are better than one, no?" The Crimson Satan smiled jovially at the Lord of Flies.

Everything started during another casual gathering between the devil kings and Saitama was invited again as well. During the conversation, Serafall suddenly chastised Saitama about how a human from another race was not supposed to butt in to devil's affair, Saitama's half‐assed motto about being 'hero for fun', and stuff about 'humiliating her'. The reprimanding led to the Leviathan challenging the caped baldy to a one‐on‐one fight. In order to avoid any unwanted attention from the underworld, the group decided to take the match at the more secluded part of the human world, where any collateral damage could be brushed off as another natural disaster.

Saitama reluctantly accepted the challenge, seeing that it was unlikely to get out of this with Sirzechs volunteered himself to serve as an overseer during the match. Ajuka was requested to accompany them in case of things were getting out of hand, while Falbium was entrusted to watch over the underworld for a short while. The Asmodeus himself also did not want to bother to go along, as much as interesting the match sounded, and the head of Underworld's Military only asked to give him the footage for him to watch later when everything was over.

"And shouldn't we stop them? I can tell that Saitama is not an ordinary person, but to pit him against someone like Serafall is still..."

"It's fine, Ajuka." Sirzechs cut off his friend. "We both know that it's useless trying to stop Serafall once she is set on what she wants to do. And I assure you, Saitama is much stronger than he looks."

Ajuka narrowed his eyes skeptically at Sirzech's smiling face, then sighing as his gaze was towards the stage to see how everything would turn out.

And speaking of those two, Serafall and Saitama were standing at the centre of the island, facing each other. Serafall was clad in her magical girl costume, along with her magic wand with Saitama in his white‐caped hero suit.

"Thanks for going along with my selfishness, Saitama‐chan~." Serafall adorned her cheerful attitude, but one with experience could tell that the magical girl was nothing but ready to fight at any moment's notice.

"It's fine. It's not like we're trying to kill each other, right? And again... I'm sorry about the other day. I didn't know that you were there." Saitama said as he walked to gain some distance in preparation for the fight.

"Ahaha, I told you it's fine~. And I also told you that you did a good job, didn't I~?" Serafall waved off. "However, a match without something at stake sounds boring, no? Let's make a wager." Serafall proposed with a gleam on her eyes. "If I win, you'll be my slave for a whole day. Of course, the same would be applied the other way around."

Saitama only blinked at the proposal, then he let out a small sigh. "...Okay."

"Awesome~! Then, without further ado, shall we~?" Serafall winked as she pointed her wand at Saitama.

"...Yeah, let's do this." Saitama remained standing on his position impassively.

And suddenly Serafall quickly took off to the sky and immediately 'glittered', sending volley of her demonic power to destroy the landscape surrounding Saitama. Her destructive attack was still much weaker compared to Gremory and Bael clan's Power of Destruction, but the attack was enough to make the island's surface be completely obliterated.

Serafall herself was holding back in her attacks. After all, she had promised to the others that she would not cause too much damage in the human world to avoid exposing the supernatural. As the explosion occurred, Serafall hovered to see any sign of life and she found a white‐and‐yellow blur zig‐zagging between the dust cloud from earlier explosions.

Immediately, Serafall dived down and gave chase to Saitama while firing a barrage of icicles at the man. At her attack, Saitama simply dodged and block the wave of ice that was coming his way. Several minutes had past, and the two kept moving on high‐speed with Saitama running across the terrain and Serafall flew after him. Serafall kept changing her attack pattern, her elemental magic, her formula etc., but Saitama either simply dodged them with enough ease or simply took it head‐on with his fist. What aggravated the Leviathan the most that Saitama's expression remained stoic, as if the man was not even trying at all.

"With strength like that... You chose to be a hero only for the fun of it..." Serafall muttered as she started to become frustrated. "Do you even know what it means to be a hero!?"

Saitama did not say anything in return as he kept moving without any sign of counter‐attacking.

"I've become a magical girl so I can teach peace, love and friendship to the Underworld! So every child can smile and I can be something that can cheer my So‐tan up!" Serafall then ascended towards the sky. "Becoming a hero with that half‐assed motivation like yours... I won't accept that kind of heroes! Magical Girls are the true heroes!"

Saitama stopped his movement at the same time Serafall ceased her attack to take off to the sky. Then, Saitama saw a giant circle with a complex code or formula written and surrounding a symbol that looked like a blue necklace, appearing before the Leviathan.

Meanwhile on the yacht away from the island, Ajuka widened his eyes as he recognized what Serafall was about to do. "That's...! Serafall, you're going too far!" Ajuka was about to step in, but then he was stopped by Sirzechs' arm. "Sirzechs, what do you‐?" Sirzechs did not say anything as his expression remained calm. Ajuka's eyebrows furrowed as he returned to watch the fight with worried looks.

"...Oooh...?" Saitama only set his sight at the glowing magic circle above him. The scale of the magic circle was large enough to cover the entire island.

"Other than simply for the fun of it, DO YOU EVEN HAVE SOMETHING WORTH BEING HERO FOR!?"

With that last cry, Serafall released her magic and demonic power and the magic circle flashed upon Saitama.

As Saitama's field of vision became white, an image from his past suddenly flashed before him.

A clean hospital room...

Fresh air from the sunny weather and clear blue skies flowing through the window, making the curtain waved as the wind blew...

A stainless, white sheet on a bed with a woman laid upon it...

The woman had long, brown hair that was tied in a ponytail, clad in a new hospital gown, was cradling a baby in her arms. The baby had a hair with lighter shade compared to his mother's...

And finally, the smile that woman showed when she turned to look at him, followed with the baby's healthy cry...

Yes...

It was the moment when Saitama found something else that became his reason why he became a hero, other than simply for the fun of it.

When the light faded, Ajuka and Sirzechs's view cleared up and they found the entire island had been transformed into a giant piece of ice floating on the sea with Serafall still hovering above it.

"...She's done it now." Ajuka said as he closed his eyes in resignation. "We have to get Saitama out of there before it's too late for him..."

"Ajuka, you're underestimating Saitama way too much."

The Beelzebub turned towards Sirzechs with slight incredulous look. The latter simply continued before the former could have asked further. "Say, Ajuka... Do you remember the day when I returned to the underworld, beaten up?"

Ajuka thought for a second before he nodded. "Yes, I remember you slacked off on your work again. Wasn't it your queen's doing? I always think that Grayfia sometimes can be very excessive with her punishment."

Sirzechs only chuckled a bit before replying. "I'm sorry to say this, but it wasn't Grayfia's doing."

"Excuse me?"

"It wasn't Grayfia's doing. I left it as it was because Grayfia advised me not to let anyone know that their leader was defeated by a human."

Ajuka blinked few times at Sirzechs answer before his eyes widened in disbelief. "Wait... You don't mean...!" Then the Beelzebub turned his sight on the stage.

"...Yes, it was Saitama‐kun who had beaten me one‐on‐one back there." Sirzechs continued with his smile still present on his face.

Serafall let out a breath as she just released her signature 'Celsius Cross Trigger' that turned the entire island into a frozen world. Only after that she realized that she had gone too far in a fight against a human. How did she lose herself? Was it simply a heat of battle? Was it because of Saitama? How come that man managed to rile her up so much?

However, while she was still contemplating in her mind, she failed to notice that cracks started to appear on the frozen island's entire surface, and suddenly...

CRANG!

A loud shattering sound was heard and Serafall's widened her eyes in shock as most part of the frozen island turned into pieces of ice in varying sizes, before something shot out towards her at the same time the island was 'shattered'.

"Whew... That was freezing in there." That was what Serafall heard a second after she saw Saitama's poker face blurred towards her and vanished right before her.

"And about your last question..."

BAM!

Serafall could not even mutter a single word out of her mouth when she felt a tremendous pain slammed into her nape, sending her back to the planet at high speed. The Leviathan finally crashed into the remainder of the island, shattering what was left into pieces as well.

"Yeah, I do." Saitama said as he let the gravity to do its job on him. "Then again, it only makes being hero even more fun than I used to think."

Back at the yacht, Ajuka's jaw was dropped at the spectacle while Sirzechs only shook his head in amusement.

During the aftermath of the battle, Falbium was actually waiting at the underground train station to pick‐up Sirzechs, Ajuka, Saitama and Serafall who just finally awoke after several hours trip back to the mainland. It was also to have Saitama go through proper procedure for travelling to the Underworld, considering that Saitama would be visiting for more occasions. When Falbium got a word about how the match ended, the Asmodeus regretted his laziness for the first time as he wished that he could have seen the fight with his own eyes.

Following the deal of the match, the loser, Serafall had to swallow her pride as she had to serve the victor, Saitama, in a maid outfit that had been prepared by Sirzechs (it was one of Grayfia's). Serafall was used to take photo‐shoots in those outfits, so wearing the uniform itself was no issue for her, but to wear such clothes while having to bow her head in front of her colleagues and serving Saitama with his irritating poker‐face (as Serafall dubbed it) on, Serafall had to threaten her friends that what happened in that train would forever stay in that train.

When they arrived in the Underworld however, despite having good intentions, Saitama only made Serafall felt bitter even more when he suddenly nulled the deal out of pity. Ever since that day, Serafall swore to herself that she would her vengeance on a certain bald man who she saw as a poor‐excuse of a hero.

The skirmish between Serafall and Saitama still happened from time to time whenever Saitama made a visit to the underworld, with Serafall wanting to prove that magical girls were better than heroes, but that was a story for another time.

And... that's it for the first chapter, folks! Many people wondered what happened between Serafall and Saitama, and this is the nutshell of it. Did I do justice in depicting their interactions and their fight? I hope I didn't make Serafall OOC or Saitama any less badass. In case of Serafall, I tried to show that the girl is not as shameless/bold as she appeared in the canon. I was simply trying to bring out a hidden/unknown side of Serafall in this story.

Sorry if the ending seemed rushed, because I think it might end up to be a mere filler if I elaborated it again. Thoughts?

And for those who wondered about the stray's appearance, it was based on The Wicked Worm Beast from Yugi Oh franchise, but bigger. I hope I can come up with better ideas if I happened have to show more monstrous enemies for Saitama to kill. Constructive reviews are welcome but flames will be ignored, so save it, guys. Ahsoei, over and out.