Disclaimer: I do not own One Piece or Naruto credits goes to Eiichiro Oda and Masashi Kishimoto respectively.
Might Duy was a tall and well-built man with high cheek-bones, a somewhat bulbous nose, dark hair, thick eyebrows and noticeable body hair on his wrists and forearms. His hair was cut in a bowl style that was combed to his right and lifts slightly. He also sported a bristling moustache with a small goatee and stubble which made up the rest of his beard. He wore a green jumpsuit, orange striped leg warmers, and a yellow scarf around his neck.
BANG!!
Ren was about to enter when he heard this sound, he look to where the sound and see an exhausted shop owner panting after carrying those weights.
"I'm very sorry, sir! You had to do that everytime i..."
"It's fine!" The shop owner assured with a smile. "It feels like I'm exercising, everytime i carry the weights you buy."
Might Duy thank the shop owner, pay and leave carrying his purchase.
The shop owner look at his long time regular customer and let a sigh "What a hard working guy!"
"Hello! I want to buy two loads of weight."
The shop owner look at Ren in surprise, he didn't think a little kid would be interested in bodybuilding, but thinking about Might Duy, he shooks his before bringing two weights at Ren.
Ren leave the shop quickly and follow Duy to see how he trains then copy it.
He follow Duy's into the woods, his brown iris suddenly turn in yellow light to record Might Duy's session in slow motion.
Finally, after hours of training, Duy's rest for a couple of minutes, then call it home, leaving Ren suspend in air thinking that his training looks trash compared to how Might Duy train.
After a while, Ren came back to his sense and in a Flash of Light, he vanish above where Might Duy training a while ago and reappeared to where he was usually training in the mountain.
After an hour of practicing Might Duy sets of training, which tired him physically, he sit down and train his devil fruit then call it home when the sun sets.
The next day, he goes to mountain, training his body to exhaustion...
The next day, he goes to mountain...
The next day...
…
That continue for a month, he would like to train more if not for his weights to break leaving him with no choice but to buy again.
As he was on his ways to find Kushina to borrow some money again, a person suddenly block his path.
"I finally found you, you bastard!" He said while glaring his red eyes at Ren.
"Hmm, let me guess... Red iris... Black hair... Arrogant... You must be from..." Ren said while cupping his chin and closed his eyes thinking then open like he suddenly remember. "...Hyuuga clan!!"
"Damn, bastard!! I'm Uchiha Kei from Uchiha clan!! I'm Fugaku's cousin and i am here to destroy you!!" The person, now named Kei, introduce angrily and said his objective.
"Fffft, Are you here because i hurt your "Baby" Fugaku?" Ren ask sarcastically.
Kei didn't reply and punched at Ren.
'How arrogant'
They were in the main street of Konoha and this Kei attack someone in broad daylight, where civilian walking.
He look at the incoming fist then punch at the same time.
BOOM!!
Their fist collided.
With Ren's fist glowing in yellow light hit Kei, his expression change.
A terrifying heat, from Ren's glowing fist, burn his fist, not only that it's explode engulfing his entire arm.
This is what scary about Glint-Glint fruit, if it cannot penetrate it will explode.
For example his fight against Fugaku, he kick Fugaku into flying without exploding because he was physically stronger than Fugaku therefore it "penetrate" his defense.
Whereas Kei is physically stronger than Ren therefore it can not "penetrate" his defense and just explode.
Impossible
Kei looks at his burnt arm in astonishment. Fugaku tells him about Ren strange bloodline limit and to be careful about it, but he didn't listen, after all in his opinion there is no Bloodline limit more powerful the Uchiha's bloodline limit.
Although the explosion burnt his arm, it did not break the bones in his arm. He's lucky that Ren is just a little kid.
Because of the explosion, people started gathering around them.
"Look a little kid manage to hurt that guy"
"How embarrassing, a kid just kick his ass"
"Shh, be quiet that guy is from Uchiha clan"
With that the crowd shut up as they know that if their comment offend the guy, the Uchiha will make their life harder.
Kei look embarrassed, although the crowd shut up, he could still feel them mocking him.
He charge at Ren again without using Ninjutsu, he didn't want to be seen weaker than a kid, then punch Ren again.
Ren didn't punch back but open his palm, a ball of light the size of a golf ball, appeared on his palm.
As Kei fist passthrough his body shocking Kei and the crowd, he thrust his palm at Kei chest.
BOOM!!
The crowd gasp and look at Kei engulfed in explosion, the explosion made Kei fly away.
"Impossible..." Kei muttered as he cough a blood.
As the smoke surrounding Kei disperse, a burnt person appeared in the crowd eyes. The crowd look at the flame burning the last bit of Kei shirt.
"What is that ball of light that can explode?"
"And how the hell did that Uchiha fist passthrough that kid's body?"
"Just what power did that kid use?"
The crowd and the new arrival crowd look at Ren in astonishment.
"Why the hell is this kid so strong?!" Kei look at Ren with killing intent.
He just wanted to teach Ren a lesson for offending the Uchiha, but he didn't expect to Ren to be this strong. And now Ren beat him up infront of many people.
This greatly shame him and for that he must kill Ren or else the clan might ostracize him.
He doesn't care and start handsign.
"Fire Release: Great Dragon Fire Technique"
A dragon shaped-head fireball headed towards Ren.
"Run..."
"Is he crazy? Using that technique here..."
The crowd running in panic while screaming.
Ren look at the dragon made of fire, put his right fist into his left palm, like he was about to pull something out of his palm, when a black shadow appeared infront of Ren and made a handsign.
"Water Release: Water Formation Wall"
The fire dragon collided at at wall made of water, then stream rose.
"Uchiha Kei, using a technique like that in crowded area, is a crime!! Are you rebelling?!" The mask man said with a cold voice.
Turn the guy standing infront of Ren is Anbu.
Anbu are under direct control of Hokage. They protect the village from exceptional threats, conduct high-risk missions into enemy territory, and deal with extremely strong ninja. They are also responsible for carrying out assassinations, tracking, surveillance, and missions requiring specially trained ninja.
"I didn't do any crime and i am not rebelling!!"
"But what you did is a crime" The anbu said while his dead eyes stared at Kei making him uncomfortable.
Kei suppressed the anger he had for Ren and said: "I am one of the team's captain. I suspect that Kaito Ren is associated to other village as a spy, so i confront him but he suddenly attack me look how miserable i am, I'm the victim here!!"
"What?"
"No one wonder that Mr. Uchiha attack him"
"So Mr. Uchiha is just doing his job as a military police force of our village"
The newcomer crowd look shock then look Ren with disgust and distance themselves.
Lies!
While the crowd who's witness everything from the start didn't believe him at all but couldn't voice for fear of being targeted by the Uchiha clan and declared as a spy too.
"Do you have evidence?"
"The Anbu has nothing to do with this."
"But if you want to arrest someone, you will need a permission from Hokage-sama." The Anbu said coldly. Infact the Anbu didn't believe Uchiha Kei at all.
'Tch, with Anbu protecting him i can't do anything... I must do something... Wait that's it!!' Kein thought then sneer at Ren.
He look back to Ren only to find the brat was about to leave "Wait!!"
"What?!" Ren look back at him with bored expression making Kei grind his teeth in anger.
"I challenge you to a life and deth duel!" Kei said confidently while inside he was hoping Ren would agree.
Challenging a kid to a life and death duel?
The Anbu and the crowd was stun at the gal of this jonin challenging a kid.
"Despicable!! How dare you challenge a kid into a life and death duel?" After the Anbu recovered he roar at Kei.
"Don't be like that, I'll give him three months to prepare." Kei said sniggering at the angry Anbu.
"So what do you say Kaito Ren, Do you dare to agree my life and death challenge after 3 months?!" Kei said smiling at Ren gently.
"Kid don't agree, he is jonin you stand no -"
"Fine i agree!"
The Anbu voice was interrupted by Ren agreeing to Kei's provocation, shocking everyone except for Kei's who's laughing happily.
"Kaito Ren you better show up after 3 months!" With this statement, jump to roofs and disappear after a while.
"Kid why are you stupid to agree to his challenge?" The Anbu asked with headache.
"It's fine Mr. Anbu i won't lose" Ren said and started leaving the Anbu just sight at that then vanish in puff of smoke.
The crowds look at the leaving Ren they couldn't help but say:
"The kid is really brave to accept a challenge from Uchiha!"
"But his opponent is jonin..."
"Three months of preparation is not enough..."
…
While Ren is on his way to find Kushina to borrow money again. The news of jonin issuing a life and death challenge to a kid and the said kid agreeing to it spread like a wild fire.