4: God Slayer Fist

Things could get worse so quickly that Jaune could hardly believe it.

Everything was a disaster: Garou, the Monster Association, the sudden large-scale attack.

Everything had gone downhill rapidly.

And now, standing in front of him with his defeated master, was Garou, transformed into a monster.

"It's you. I didn't expect us to meet again like this" Garou seemed relaxed, his posture exuding unmatched confidence.

"But it's good that you're here. You were my first prey and my first failure. It's time to rectify that. Your defeat will mark the beginning of my absolute rule"

Jaune didn't speak; the time for that had passed. He didn't believe he had any chance of defeating Garou anymore.

If his master had failed, what chances did he have? But even if he couldn't do it, he had to try.

The fight was one-sided at first; Garou was content to toy with him, demonstrating his superiority and boasting about his strength.

That began to change slowly but steadily.

"This feeling!?" Garou opened his eyes, recognizing a familiar sensation.

His strike was deflected and countered; this should be impossible.

Every move that followed, every attack deflected and countered, only made that feeling of familiarity grow in Garou's chest.

"Damn it!"

Jaune and Garou, they didn't know each other very well, hadn't spoken much, but they had practiced together a few times.

Both of them used the Water Stream as the central foundation on which they built their strength. This was truer for Jaune than for Garou; the Water Stream was the martial art he had grown up with and upon which he had based his growth from a defenseless child to a Class S hero.

He might have learned other martial arts before realizing the truth in the currents of the Water Stream, but that didn't change what the core of his martial arts was.

Garou had also taken the Water Stream as his core; it was the pillar of his strength and what led him to make his fist perfect.

What had led him to the pinnacle of martial arts.

And for that reason, he couldn't defeat Jaune. It was like it was their first fight, the fight that Garou had lost but with the roles completely reversed.

Jaune was using the Water Stream to tap into Garou's energy flow and copy his technique.

Jaune wasn't a genius, but the martial art his master had created was so incredible that it allowed him to grow as quickly as a genius, even faster, thanks to Garou.

Realizing this, Garou attempted the same as Jaune, to break the flow and thus end the fight.

It was a pity for Garou that Jaune wasn't the same; he knew that the flow could be broken, so he didn't limit himself to the Water Stream. Every time Garou changed his style, Jaune followed suit.

All the martial arts that Garou knew, Jaune had also learned. Every style that garou stole, Jaune had learned it the right way.

Even if Garou pulled out a style that Jaune didn't know, he could still keep up and instantly mimic that style.

Then there was resonance.

Even if there was an enormous difference in their raw power, the extremely similar nature of that power and the flow of energy currents created resonance and exponential amplification.

Jaune began to catch up to Garou quickly.

"Impossible!?" Garou couldn't understand it or believe it.

Something of this nature was beyond even his comprehension.

For a brief moment, Garou considered giving up the fight, but at the same time, he realized that his strength was also growing.

This was an opportunity!

He didn't think it was possible, but in reality, he was getting stronger. He believed he had already reached the absolute peak, but now he knew it wasn't the case.

So the battle continued, and Garou decided to fight for real.

"Monster Calamity God Slayer Fist!"

"God Slayer Instant Attack!"

"What!?" Jaune barely managed to deflect the thousands of strikes directed at him in an instant from what seemed like all directions. Garou's attack almost overwhelmed him completely.

"Amazed? This is the pinnacle of martial arts! The culmination of all the styles I've learned brought to perfection, the Monster Calamity God Slayer Fist!"

"Tch! I didn't expect you to have the ability of an eight-year-old to name your techniques... but since that's the name you've chosen, I'll respect it! God Slayer Instant Attack!"

Of course, Jaune wouldn't fall behind at this moment, not when miraculously beyond his comprehension, he was keeping up with Garou and not losing completely. He returned the attack, not perfect yet, but a nearly exact copy, which was enough to catch Garou by surprise.

Their fists struck, but Garou's monstrous body was harder and more resistant than anything Jaune had ever faced.

"Hahaha! That's right! Get stronger! You'll only make my own strength increase! I thought my fist was perfect, but it seems there's still room for improvement. Let's perfect my martial art beyond any limit!" Garou laughed with excitement and quickly advanced.

"Whirlwind Calamity Cutting Fist!"

In the distance, a mountain was cut into pieces, the extremely thin and compressed air currents were more deadly than any other attack Jaune had faced, and he barely managed to dodge it, but the damage was evident, deep cuts spread across his body.

"Do you like it? It's an upgraded version of the old man's brother's technique," Garou smiled, his sharp teeth gleaming in the moonlight.

That smile vanished when equally sharp and cutting air currents nearly blew his head off, and the ocean split behind him, revealing the seafloor.

"Don't be arrogant. You may have copied that technique and think you've improved it, but I learned it from the true master." Even as he said that, Jaune had to admit to himself that Garou's version was vastly superior, and that's why he copied it.

"Tch! You say that and yet you use it, you bastard." The fight didn't stop because they exchanged words; the speed at which they moved left residual images that created a trail that soon resembled a formation of lights in the sky.

Like a constellation on the rise.

Jaune set aside all other thoughts, his mind focused solely on defeating the enemy before him, every move, every breath, every moment.

All his focus was on defeating Garou.

If this were a duel between two humans, then a fight like this wouldn't have a winner or loser. Neither of them would be the victor. Unfortunately for Jaune, he was only a human, and his opponent was already a monster.

His wounds continued to accumulate, and Garou regenerated at an impressive rate, undoing any damage Jaune managed to inflict.

In the end, the outcome was decided before it began, and although Jaune knew it, he didn't give up, even when his body could take no more.

"Truly, you're surprisingly persistent. It's a shame; a human can never compare to a monster like me. This is the end," Garou relaxed, looking at his opponent who was staggering in front of him, missing an arm and with a large hole in his side.

It was truly a pity. If they could fight a bit longer, exchange a few more blows, Garou felt he could overcome an invisible barrier.

But it didn't matter anymore. His strength was now incomparable; no one could match him.

He stepped back, ready to begin his final hunt.

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Jaune could no longer see; his blood-filled eyes had clouded, and his other senses were becoming numb.

Had he failed? Even though he knew he couldn't win, it was still bitter, really bitter. He was going to die again; he could feel it.

Although it was only a little longer than his previous life, he had come to appreciate this new life. He had truly achieved many things, hadn't he? Though he failed many times, he succeeded in many others. He couldn't accomplish everything he set out to do and left many things unfinished, but at least in this life, he truly wasn't a disappointment.

He had come quite far, but everything had to end at some point... truly disappointing.

He wanted to do more; he wanted to live longer. He really wanted to go further.

There was the sound of something hitting the ground, a faint tremor.

"What are you supposed to be?" a strange but familiar voice reached Jaune's ears. Although he couldn't hear it well anymore, this voice sent an unprecedented sense of relief.

A smile spread across his haggard face, and his body finally gave in and began to fall.

"Huh? Who the hell are you?" The sound started to become fainter, but he didn't care anymore. Now everything was okay. So what if he had failed? In the end, all he had to do was buy time.

"What am I supposed to be, you ask?"

"I am Garou, the monster."

Garou began to rant, but Jaune no longer cared. Now that everything was in its place, he let his body relax, the cold embrace of death beginning to take hold.

He truly hoped his master wouldn't be too sad. In the end, it was his choice to end this way. He wondered what would come next. What is there after death when you die a second time?

He hoped there were comics and video games, as it would be really boring if there weren't.

"Everything is in your hands now, Saitama."

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"Ja..."

"Jau..."

"Jaune!" He awoke with a start, his eyes snapping open, and his body leaping up in the air, landing agilely in a combat stance even before he knew what was happening. This sent a mild shock of pain through him, muscles that had never been used this way were suddenly pushed to their limits, causing Jaune to feel an improper stretch. This had never happened to him; his body had long become accustomed to moving in sudden bursts of speed.

Now, it seemed like his body wasn't ready for such movement.

"Everything okay in there, Jaune? I heard a strange noise. Anyway, come down! Breakfast is almost ready." A vaguely familiar but unfamiliar voice called him. Jaune blinked in confusion before taking in his surroundings.

It was a somewhat small room, with video game and comic posters adorning the walls. A TV was in the corner along with what appeared to be a video game console. Some books were scattered on the floor, and action figures were on the shelves that decorated the walls.

A window let in the gentle morning sunlight. Jaune rubbed his eyes and began stretching, feeling his body in a strange way.

Looking at himself, he seemed to have shrunk. His muscles had disappeared, and he felt weak—very weak, extremely weak, like weak to the level of an insect. Well, maybe the last part was an exaggeration; insect-type monsters were probably stronger than he was now.

With no small amount of confusion, Jaune searched for a reflective surface, opting for the television. As he looked at himself, he couldn't help but blink several times—blue eyes, blond hair, and a bewildered look.

"What the hell?"

"Jaune, come down!" another shout, and Jaune rose.

Jaune? That was his old name, right? How did someone else know it? He had never mentioned it to anyone.

Nevertheless, he responded. He was weak, very weak. The simple action of quickly assuming a posture and feeling his body ache as a result demonstrated this. Engaging in a fight now wouldn't be smart.

"I'm coming!"

So he opted to be peaceful until he figured out what was happening, although judging by what he had gathered so far, he had a vague idea in his mind.

"I really can't stay dead, huh..."

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End of prologue
Note:
What do you think? It's an idea I had when I looked back at OPM's manga, I always thought it would be quite interesting to write about his martial arts and because of all the research I've been doing on RWBY for another story I thought why not? There will be flashbacks of Jaune's time in the OPM universe since I think there were things missing to describe but I felt that putting all that in the prologue would be too heavy.

Jack-21 said: teres one problem with this, Jaune in this fic got strong due to hard work as you have wrote it but after a certain point, Jaune should simply not have been able to keep up with Garou.

For example, the Cross Fang dragon slayer fist can not be used even by a world class genius normally, it's directly said from the manga. Both bang and bomb have to perform together to actually use this art even though both know how the art is supposed to work as it's a fusion of their respective martial arts.

Jaune should have been simply stuck on copying it even though he knows how a proper user would perform it due to its complexity

here is a perfectly canon explanation! There are two forces working together in this, the first is resonance! In the manga it is explained that when two forces, powers, etc., are equal and similar enough, then there can be a resonance that amplifies said strengths in both directions, this is how Metal Bat became strong enough to damage a monster higher than the level. Dragon Even though he couldn't previously claw at a dragon level like Elder Centepide, Garou literally made Metal Bat's strength get bigger and at the same time he also got stronger! The second force here is flow! the same thing that garou uses to copy anything and adapt it to him, this flow is important since it is what made the resonance exponential, two identical forces (same martial art, same bases, same master) guided by a similar flow growing exponentially. It is like a yin and yang, where one feeds the other as mentioned, if it were a fight between two humans there would not be a winner but unfortunately for Jaune Garou he was already a monster and that is why he lost. So to summarize: Garou enhanced Jaune as much as Jaune made Garou's strength grow by allowing him to further perfect something that he already believed to be perfect. It is as if for that brief fight Garou shared his talent with Jaune in order to have the best training partner possible. At the same time, Jaune also has his own merit because if it weren't for the fact that he himself understood the flow that Garou uses and also studied many styles of martial arts before, he would never have been able to keep up with the rhythm and stay in the flow and follow the resonance. So if Jaune for a brief moment was as talented as Garou and reached the highest dragon level strength as a human, he still lost but you know what they say, take what you can.

an answer to another question that was asked to me on another site that I think can help clarify doubts so I am uploading it here as well as part of the information of the story.