Disclaimer: I don't own Kenichi the Mightiest Disciple.

*Re-done on 4/17/2020*

Kenichi the Invincible Disciple

Meet the World's Mightiest Student

"Well…" A young boy with black hair and wearing a plain blue workout uniform with leather sandals looked at a sheet of paper in his hand, with an address written on it. It led him to a large entrance way with a pair of doors were as tall as trees. "Seeing is believing. Here we go." His name is Kenichi and while he might not look it, he is the single most dangerous person in town or better yet, this side of the Earth. "No doorbell, I better knock." And by 'knock', Kenichi practically sent the doors off their hinges. "Who makes these things weak anyways?"

Aside from the doors littering the yard, the inside was a dojo complete with wings for sleeping and eating. "Is everyone on break or something?" Kenichi was still no bothered that he unhinged the doors and helped himself to the sights until,

"Hey brat!" Kenichi turned to a large man with the glare of a demon but the former was still not flinching one bit. "Yes, I mean you. What the hell are you doing here? For that matter, where is the stampede that knocked down my doors?"

"You must be hard at hearing, geezer. If there was a stampede then there would be an earthquake but sorry for knocking too hard anyways." Kenichi said that in one breath and started to walk away but the old man was not done with him.

"So, this damage to personal property, followed by breaking-and-entering is your doing?" The chuckle in his tone made it clear that the old man was not buying Kenichi's story, not that mattered to the latter. "It seems that children must be disciplined to respect the needs of others and especially their elders…"

The old man soon noticed that his vision of field suddenly spiraled and the ground meet his back rather hard, as if it was trying to shatter his spine. "Sorry you geezer but I am only here for one thing and you are only wasting my time. But do you live here?" Kenichi immobilized the giant of an elder with a hand on the left wrist and a foot where the arm is connected to the torso. The old man grunted and tried to move Kenichi's leg but it was as bad as a vice grip. "Then do you know a Miu Kurinji?'

"Grandpa!" Both Kenichi and the old man heard a young woman's voice and see indeed a well-shaped female teenager standing in full view with a training uniform. "You!" She pointed a shaky finger at Kenichi, like the sight was scaring her to death. "I never suspected that you destroyed our doors and be able to subdue my grandpa but you are not going to finish me that easy!" She then charged in with a fist ready for the kill when,

"Miu-chan, don't! He is far too strong to measure!" The old man shouted but the girl couldn't stop in time and her fist landed on Kenichi's chest. Nothing happened for a moment, right before Miu leaped back with a hand with busted bones. "Miu-chan!" The old man struggled more to treat to the little girl until Kenichi let go off his arm.

Kenichi then walked over to Miu and gently grasped her arm with the busted hand. "Hey! What are you doing…!?" She was ready to hit Kenichi again when the boy gently took her hurt hand and kissed on the back; one that caused the hand to glow and fully healed in seconds.

"A kiss always helps heal the pain, remember Miu-chan?" Kenichi talked like this girl was his old friend from who knows when. In this instance, that seemed to be the case. And Miu sure did remembered Kenichi.
"K-kenichi-chan!?" Miu's started to shake again but for reasons other than fear. Then she suddenly embraced him. "Oh Kenichi-chan! I am so sorry! You look so different that I had no idea it was you! I am sorry for attacking you! I am sorry!" Miu went on and on until she buried her face into Kenichi's shirt but the man himself was facing the elder still on his knees, nursing his arm.

"Do you have any Oolong Tea? I won't mind a cup or five." The old man just chuckled with amusement.

XXXXX

Later,

"Ah, this tea is good and warm." Kenichi relaxed in his seat with a cup full of Oolong tea in his hand. Still his eyebrow twitches that one of his arms was starting to feel numb from the pressure of having a well-rounded woman cling to it, as if it was a lifeline. "So Miu-chan is your granddaughter, Hayato-san?"

The old man nodded while sipping his own tea, liking the Oolong brand too. "Indeed. I didn't just find her and adopted her. She is definitely my paternal granddaughter, although her parents are best not discussed."

Kenichi looked back on Miu who still looked content with a smile on her face while his had a small frown. "I had no idea. And I still have my folks and adorable little sister accounted for. I should invite Miu for my mother's dinner, it is to die for." This caused the old man to chuckle yet again.

"You just met her today and already you want to introduce her to your folks?" Then Hayato got his devilish look again. "While she might know you, I don't want any engagement until you started dating." While Kenichi was obviously not scared somehow, he still nodded. "Still, how did you know you granddaughter?"

Kenichi smiled for a moment and then frowned again. "I will tell you later. But you can tell me about this!" Kenichi suddenly smashed his left hand into the floorboard, so loud that it spooked even Miu. And out of the floorboard came an old man with a camera and a bloody nose with his head in Kenichi's grip.

"Kensei! Again!?" Hayato was no happy about this either and seemed to know this old man. This geezer can be described as a fairly short middle-aged man, who is balding with a long pointed out Chinese mustache. He wears typical Chinese clothing used in martial arts with a hat. "We have a guest and you have the nerve to spy on us, especially my granddaughter with that camera of yours!?"

"Sorry Hayato, I couldn't resist." The old man named Kensei responded sheepishly, not the least bit ashamed. He was only feeling pain from Kenichi's grasp on his head and hat, it was starting to draw blood. "So, who is this kid daggling me along like a caught fish? And how on earth is this grip so strong?"

"I guessed that much already Kensei. He was the one who demolished our front doors, trying to 'knock'." Hayato answered. "Now Kenichi, this is Kensei Ma who lives in our dojo as a resident martial arts master. He is the only man in the world who has mastered all forms of Chinese Kenpo."

"Impressive, and your forgot that he is a career pervert and expert peeping-tom." Kenichi said with his deadpan voice, almost being sarcastic too. Hayato had nothing to say and just nodded. "So, tell me how many times he did this to Miu-chan. Or I will crush his head worse than an acorn."

"You will have to knock me out first!" Kensei proclaimed and before anyone could warn him, the old man struck Kenichi in the chest. Like before, the sounds of bones breaking were heard and followed by the howl of the owner and it was not Kenichi. "What the hell!? Your skin is tougher than steel!"

"Heard it before old man and you should tell me how many times you molested Miu-chan or else I will have to rip open your skull and see for myself." Kenichi spoke and actually scared the old man with the genuine threats in the former's voice.

"Please stop Kenichi-chan! Kensei-san never did such a thing! He is not the type! Please don't kill him!" Miu finally found her voice and pleaded for Kenichi. After gazing into her eyes, the young man released the old man but before Kensei could flee,

"Just go and find some other hobby with that damn camera of yours. Do bird-watching or something and keep your eyes to yourself." Kenichi muttered. After the old man was out of sights, Kenichi let out a sigh like he was having a headache. "Is he the only one that paying rent in this dojo?" Both Hayato and Miu shook their heads. "And all of them are like that guy?" They shook again, to say that Kensei is the only one. "Then can I meet your other tenants?"

XXXXX

"So, you old fart, who's the kid with the funny outfit~!" Kenichi felt a terrible itch on his forehead to itch. Hayato led him to another room that was currently used by another giant of a man that was letting himself go with the sake, given his bad breath and the empty bottles littered around. This was Shio Sakaki, the 100th degree street fighter. "He looks so stupid with that suit! He will never survive here! Scram, you little urchin~!"

Shio went for more sake only to notice that the floor was bare and clean around where he was wasting away. That got him to get on his rear and saw the entire room had been cleaned in an instant. Shio then saw Kenichi gather everything into a single trash bag. "Hey! I wasn't done with those!"

"Yes, you are." Kenichi retorted. "All this drinking is going to poison you one day and you can't defeat that with karate." The boy in question went back to tying a robust knot with the bag and Shio felt the need to get up, walk over to Kenichi and get physical with him. Except Kenichi didn't even budge.

"Arrgh! What the fucking hell!?" This was getting old and it showed on Kenichi's face. "What is the hell's wrong with you!?" Shio clutched his wrist with his hand actually limp and lifeless.

"You need to learn some manners and how to make a better first impression." Kenichi remarked in his monotone. Before Shio could retort, a hand chop near the speed of sound had hit him at the right spot on his neck; the large and drunk man was out like a light. Then the young boy turned to Hayato, who is not looking too pleased with how his tenants so far are treating their guest. "Are there anymore?" Kenichi sounded bored and Hayato couldn't blame him.

Shortly afterwards,

"Who is this boy that disturbs my pleasure time?" This one was rather calm and self-contained, and a woman to boot. She was rather beautiful and her room spoke for itself; she loved weapons. Her name was Shigure Kōsaka, the Maiden of Arms. "If you two don't leave then I will have to sully my blades with his blood." And immediately, Kenichi had a katana posed for his throat, not that he was in any real danger.

"Go for it. I haven't gotten as much as a cut on my wrist in ages." Kenichi said without any fear whatsoever, not to be courageous but instead to bored of the threatening from the tenants. It has gone to the point that one more pout of hostility will change Kenichi's mind of training at the dojo.

Immediately, the sound of metal breaking was heard Shigure looked horrified to see one of her blades fail to kill; in fact, it failed to even damage Kenichi's skin. "I am no expert but I can tell that blade of yours is cheap spare to use. Best save your favorite sword for later." Kenichi then walked off and Hayato left without even looking at Shigure in the eye; that was how the old man was disappointed, getting worse by the moment today.

"Ah, a guest. How quite." When both guest and host wished for a tenant to not be hostile for once, this was no what they had in mind. This guy wore a thick robe, had killer facial hair and never let his eyes of his book. This was Akisame Kōetsuji. "Just show him to the others while I finish my reading."

"Well that was boring, old man." Kenichi had nothing else to say. "Unless there is more, I am leaving." Hayato didn't need to say a word and pointed over to yet another tenant, one that was playing…with ants.

"He is the last one, Kenichi-kun." Hayato said. "He is the most child at heart despite once being a fighter ring champion by the name of the Grim Reaper." Kenichi raised his eyebrow in interest rather than confusion or annoyance. "His name is Apachai Hopachai, master of Muay Thai boxing."

"APA!" The large man with a childish face suddenly shouted. "Apa says hello to master and little guest! Apa thinks the day is great!" He is extremely tall and powerfully built, has tanned skin, short spiky silver hair, and is usually seen wearing a yellow tank top and red shorts and a mongkol around his head with bandages wrapped around his hands and feet.

"He certainly is 'friendlier' compared to the rest of your cash cows." Kenichi replied bluntly and Hayato shrugged, there was nothing more to say about Apachai; a man with nearly unstoppable power with a childish face and a personality to match. "Now that I have seen enough, I have something to say."

"Yes Kenichi?" Hayato replied but Kenichi was silent and faced Hayato directly. For a moment that felt painfully long, something started to ripple throughout the garden that got the resident's attention. Miu arrived along with the other tenants to see the same kid staring down the old man with strong auras burning to see. The whole scene looked like two predators staring each other down to prove who was the more dangerous of them all. Then the ice was broken when Kenichi let out a sigh and letting his aura down while Hayato did the same.

"You know what, how about a duel between you and me." Kenichi suddenly said and that caught everyone off guard, especially Miu and her grandfather. "After all, a dojo's good name is not from just the students but also the teacher and owner. And since you are both the teacher and owner, I will like to fight you. You are the Mutekichōjin (Invincible Superman), a perfect match."

XXXXX

Later, on an open field within the dojo,

"Look Kenichi-kun, I suggest you reconsider. You may have knocked down those ten-ton doors and took hits like a hall to cannonball but I have been fighting all my life." Hayato tried to talk down Kenichi will a fair warning. "Not just I will lose sleep for hurting a little kid but think about this for my cute granddaughter. Don't die on the same day you two finally met again."

"Thank you, old man." Kenichi replied in his usual deadpan. "But I am serious. I am strong if there was any definition to the word. That is my pride and my problem." Kenichi continued before pausing. But that moment suddenly felt like the blink of an eye when the young man charged towards Hayato like a raging bull.

Hayato simply moved his hand to catch Kenichi and maybe throw the boy over his shoulder. But unfortunately, it was not to be when the boy landed a punch into the old man's chest. The impact caused Hayato to cave in and that was when Kenichi moved again, landing a kick to the chin. And this one was strong enough to see the old man's head up nearly fast enough to snap the neck; instead a tooth had been broken and another fallen out.

"You…" The old man realized that he let his guard down judging Kenichi to be an average high schooler. Hayato then moved in on Kenichi, looking a demon once more. But instead the old man's punch landed on the ground instead of Kenichi. And that was because the young man was suddenly on the other side of his opponent, with his hand clutching Hayato's opposite wrist.

Hayato was moved into a rather painful ride on Kenichi's shoulder. And it was not better for his back hitting the ground. Humiliated and confused, Hayato let himself go more by just a smidge. And by a smidge, that meant the old man went from physical to mystical with a shockwave emerging from himself; thankfully none of the watchers were harmed.

"That was cool. I will love to learn that one." And apparently, Kenichi wasn't hurt either. But that was not on anyone's mind at the moment. The men nearly unhinged their mouths while Miu and even Shigure were blushing. The shockwave had burned off Kenichi's blue jumpsuit and even some of the matching trousers, revealing the muscle god underneath.

"…he kinda looks like you, Same." Shio whispered to the philosopher, "Only with a few more pounds on a lot of places." Indeed, not a single piece of fat was in sight and even above the neck, the skin was on Kenichi's entire body like a tight-fit full-body spandex suit. It was so intense and so shocking that Miu practically smells the blood dripping out of the nose and the taste the drool leaking out of her mouth.

Then something happened that none of them counted on, not even with all their imagination. Kenichi moved a finger, shifting the atmosphere significantly, and placed two fingers to his ear. "…yeah. Just another trip to the dry cleaners…" Kenichi mumbled and then perked up, "…not kidding? How convenient and I mean it. Is it the one above this location?"

Kenichi lifted his head up to see what appears to be a simple passenger airplane. "…Understood." Kenichi mumbled some more and lowered his fingers, then he faced everyone watching. "Don't blink because you can miss it. This is a mere demonstration that I can give for free."

Before anyone could respond, Kenichi moved his impressive body to a rather simple posture with his right hand ready to see a punch. Hayato was about to take it until he noticed the Kenichi was aiming at an entirely different angle; one that is facing the sky. Then it happened, faster than sound, Kenichi set off a sonic boom right at the sky.

Apparently, that airplane had moved into a thick cloud in a rather suspicious fashion and yet it didn't protect the plane from a force emerging from the dojo that tore through every cloud in its way. Everyone just saw that cloud head turn red with fire. It looked like it turned into a raincloud that didn't pour down water droplets, but embers and pieces of metal down to the ground.

"I haven't fully introduced myself since I figured that one of you had heard of the one man in the whole world that has a license of kill." Kenichi spoke similar to a disappointed lord looking at his underlings that let him down. "I am more than a freshman in high school and childhood friend of your granddaughter, Hayato Furinji. I am an international, plain-clothes assassin that is registered by all main countries. While on duty or out in the open, I am known as the One-Punch Kid." Seeing that everyone was on the verge breaking down, Kenichi finished the job. "And I am here because of a promise made to Miu-chan a decade ago, that I will come to her home and learn martial arts. I intend to do good on my word and I have made up my mind on which style I want to learn." The air couldn't be more tense when the five masters felt the boy staring them down. "And…I want to learn them all."

End of Chapter 1.

*What do you think? I had not made this a crossover since there is only one element from One Punch Man to appear in this story, none of the characters from that manga series will appear; this will more focused on Kenichi History's Mightiest Disciple universe. Let me know!*