Many years ago, when Ryuu and Kakashi were still captains of Team Ro. After the tenure of the fourth Hokage, Minato Namikaze, Ryuu, and Kakashi aimed to become stronger; this time, it was Kakashi's training day.
Ryuu and Kakashi were at the training grounds, their favourite, the third to be exact.
There was a launching of multiple targets, several targets up in the air.
"Lightning release!" Kakashi yells, making a hand seal.
Bzzt!!!
A surge of electricity crackles, forming from his body, travelling and touching, and frying everything in its path. A huge flash of lightning brings a thunderous explosion.
Boom...
Finally, as the air relaxes again, the smell of burning wire fades, and the training grounds remain the same again.
Huff... Huff.
Kakashi catches his breath. His knees buckle as he tries to recover.
He feels a hand on his shoulder, helping him up, "Nice try, new record." Ryuu says.
Kakashi looks up to see Ryuu. "Yeah, I still haven't got it yet." He says while getting up.
Ryuu walks ahead, off the water. "Want to share a bento box with me?" He asks.
"Yeah, sure."
With that said, the two brothers sit under the shade of a tree with chopsticks as they eat their bento box.
"I can't seem to get it right." Kakashi says, before stuffing another piece of pork.
"Black Lightning is a special technique." Ryuu says, "It's not too surprising that you'd struggle with it. I mean even I can't pull it off sometimes. It requires absolute focus; striking through and beyond anything." He reaches in for another piece of pork.
"I get it." Kakashi says, "Lightning release is the most uncontrollable nature release. Lightning as a whole has a dangerous and uncontrollable build. With black lightning, you'd need perfect control of chakra in order to strike with precision. You'd need to follow through, match speed, intent, and strength. Akin to resonance."
"Exactly." Ryuu says, stuffing his mouth with an onigiri. "That said, Black Lightning is powerful for a second reason. If and when the user matches all requirements, speed, strength, intent. Its difficult to explain what happens when I hit Black Lightning with a perfect strike. It's the closest we'll have to reaching the maximum volume of a ninjutsu. Not even I have ever hit too many at once."
"I see..." Kakashi says as he takes his final piece. "Well? How many have you hit in a single battle? What's the record?"
Ryuu arrogantly points at himself, "Since I'm the greatest shinobi ever, my fights rarely get far enough for me to hit as many. But... five!" He says aiming five fingers in front of Kakashi's deadpan face.
"Five huh? Was there a difference? Did you feel something?" Kakashi curiously questions.
Ryuu put his hand on his face, pondering, "To be honest... I don't know. I could only focus on the enemy ahead at the time. And ever since, I used to combine black lightning with lightning blade. Even the third Raikage only used it twice."
As Ryuu reaches into the bento box, he realises its over, "Hey! What happened?!" He yells angrily.
"I'll buy the next one." Kakashi says with a smirk.
From the tree, a man in a mask hangs upside down. "Yo! Tenzo!" Both Kakashi and Ryuu call his name.
Tenzo removes his mask, looking away in annoyance. "I told you guys not to call me that." He mutters,
"That's Captain Kakashi and Captain Ryuu to you, you know?"
Kakashi and Ryuu glance at each other, smirking. Annoying Tenzo was always a hobby of theirs.
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Kakashi breaths heavily, his Sharingan turning off as he connects with the perfect black lightning against Matatabi!
"Aaah!" Matatabi screams in pain, as lightning courses through her body.
"Son Goku! We have to attack together now!" Gyūki commands,
"What?! It's just one man! He's low on chakra." Son Goku argues.
Gyūki looks back, preparing a tailed beast bomb yet again.
"That attack, that variant of black Lightning does more damage to a tailed beast than a human." Gyūki says, shooting another bomb at Kakashi.
Boom!!!
A beam made completely of chakra, destroyed everything in its path! The collision creating a crater, and tearing the ground apart.
"Gyūki, what has gotten into you? Don't be reckless." Son Goku yells.
"The jutsu which Kakashi Hatake has used is the one the third Raikage used in order to weaken me in our fight.
Black Lightning is a cancer to anyone with high amounts of chakra. Those like us, created completely out of chakra, we are completely exposed to its effects.
The lightning coming from black lightning strikes the tissue just as much as it strikes the chakra system. Spreading and constantly compressing rapidly, to create a null effect in our bodies.
Additionally, it's near impossible to use any black lightning more than twice. You'd have to reach impossible extents of concentration."
The smoke from his attack begins to fade. As he searches for Kakashi, Gyūki sees the destruction their fight has caused. Thousands of acres destroyed, patches of water created and an entire crater formed. The world will take years to heal.
"Is he gone?" Son Goku asks, unable to sense Kakashi's presence.
Whoosh!
As if he was summoned by the mere mention of his name, Kakashi reappears in a blur.
His eyes glare at Son Goku while he carries lightning in his hands.
"No!!" Gyūki goes to punch Kakashi.
Boom!!
"Aaah!" Son Goku cries out as he's moved back a few steps.
'What?' That's when he realises.
Kakashi's visage vanishes like smoke!
'A clone!'
Looking behind, Gyūki sees Kakashi as he carries a blade sparkling with black lightning.
"Black Lightning!"
Boom!!!
The attack sends shimmers of Black electricity coursing through the eight tails!
"Gyūki!" Son Goku rushes in to save Gyūki.
"No! Stay back!" Gyūki manages to cry out. But he's too late, Kakashi runs towards Son Goku.
"I won't let you!" Son Goku spews out lava from his mouth, making a circle of molten rock around himself.
'That's as expected.' Kakashi ponders. He stops running and stands on the water. Clenching his fists.
Poof! Kakashi's body disperses.
"Now you've created the perfect environment." The real Kakashi claims as he makes multiple hand seals, creating sparks of lightning in his hands. He stands defiantly above a tree on the shores. Th
"This will be our final fight!"
Raising his hand for this move,
"Begone with the thunderclap."
'Kirin!'