First off I wanna say this. I'm a little disappointed I never really saw a fight between these two vision based Kekkei Genkai. I've seen Sharingan vs Sharingan, Byakugan vs Byakugan, but I haven't seen these two against each other. So here's that.

Flashback to the work study with Ochako, 3rd person POV:

"Hey Ms. Konan, why is the Sharingan so special?" One day after training and achieving second stage for her Sharingan, Ochako decided to ask a rather odd question about her unique vision jutsu to her teacher. "The Sharingan is a very powerful and deadly technique that only the Uchiha are able to use to it's fullest. You see, only the Uchiha can grow it stronger and use it with very little drawback on them. If someone else were to obtain it who does not have Uchiha blood in them, the drawback on their body would be extremely severe and they would only be able to use it to the best of it's growth when the eyes were implanted in them." "So why would someone want it?"

Konan began looking at Ochako before answering. "Among the abilities of the Sharingan, there are three unique functions of it. The first is it's ability to analyse the situation around them and show them to you at slower speeds for you to react faster. Your ability to react to things are severely increased because of this. The second is it's ability to copy the movements and use any jutsu that is not Kekkei Genkai based. Even if you are not of this base element and specialize with it, you will be able to use it with the Sharingan. The third and final is something only Uchiha can use it to the fullest. They have the ability to manipulate illusions in this world to levels that even death can be looked at as false with you." Her eyes went wide when Konan said even death can be reversed with the power of the Sharingan. "Without a doubt, the Sharingan was one of the two most sought after visual jutsus that the hidden Leaf had when they were around."

The fact this wasn't the only surprised the brunette to ask about it. "What was the second?" "That would be the Byakugan. A near impervious defense that also allows the user to see distances along with the chakra network in a human body. When this is merged with the intense training the Hyuga clan puts their children who develop this skill through, the user is near impossible to land a blow with them not realizing prior to impact. That is, if you can land your blow without being taken down. Because of their power, many battles were fought with hopes to obtain one of the two if not both." Ochako thought on her Kekkei Genkai and the one she just learned of to know they are some of the more powerful of jutsus others tried to take to better themselves. 'A Kekkei Genkai that allows you to have a near impervious defense. That's scary.'

Back to present

Izuku and Ochako had traveled at their max speed to make up for their lost time until they were in a clearing. There, they were faced with another opponent who was not letting them go past.

"Grrr, I AM SO DONE WITH THESE THINGS!" Izuku and Ochako started channeling their chakra in their hands while the beast with it's bones on display came at them. "OUT OF OUR WAY! CHIDORI/RASENGAN!" Both landed a blow on the monsters chest to blast it to smithereens leaving only the limbs of what it was left. "That may have been a bit overkill Izu." "At this point, I don't care. We need to finish this mission so everyone's sacrifices wont be in vain." They started moving again before a second person came at them "Gentle Fist!" Izuku barely dodged the attack before attempting to attack the unknown person to be countered and nearly hit again if he didn't turn to paper at the last minute. He reformed beside Ochako for the person to show his face.

"I apologize to whoever you are, but I am unable to allow you to pass." Izuku was fit to be tied with Ochako stopping him. "Izu, his eyes." Izuku calmed himself enough to know something was off with the man's eyes. "Who are you?" "When I was alive, I went by the name Neji Hyuga. A member of the Hyuga clan." "A Hyuga, never thought I'd see one up close and personal." Ochako began activating her Sharingan and standing in front of Izuku. "I've got this, you go the longer way around. At max speed, I'm sure you can  reach the destination faster than if we were to go straight." "I'm not leaving you as well." "We don't have a lot of choices. If we both team up, we'll most likely lose Bakugou. All I have to do is stall him." "But-" "NOW'S NOT THE TIME FOR BUTTS! It's either we do this, or we jeopardize everyone's sacrifices up till now." Izuku gritted his teeth while nodding. He gave her a peck on the lips before running and creating wings to move over the trees to cut a bit of time off his travel.

Before Neji could go after Izuku, Ochako began making handsigns to attack. "Fire Style: Phoenix Flower Jutsu!" The attack came barreling at the reborn Hyuga clan member with him countering. "Rotation!" Keeping him from having a moment to stop, Ochako came at him with a lightning infused kunai. Neji began dodging a ruthless assault with speeds to rival All Might for Ochako to not comprehend why she can't hit him. 'Am I moving too slow, or is he just faster?' She was sent flying though when she was hit in the stomach by four quick jabs. The brunette slid back coughing up a little blood. 'What was that about?' "Be warned, your chakra flow will be irregular now. I had hit four of the chakra points in your body right now." "You what!?" "It is a technique of the Hyuga that allows us to weaken our opponents along with limiting complications for us. We just simply block the flow of chakra for some time to put more strain on our opponents. Do not take too many of them."

She began to worry now knowing frontal won't work. 'Ok, so he can force me into a corner if I keep close range. I'll just fight long range then.' "Eight Trigram: Vacuum Palm!" Ochako dodged with the side of her sleeve being ripped off. "That wouldn't have ended well if I took that head on." 'Guess I have no choice.' Ochako began using genjutsu with her bells thinking she could take Neji on without worry. 'I've got him.' "I'm sorry, but that will not work on me." 'What?' The reborn Hyuga was able to pinpoint her location and hit her with a Gentle Fist to the rib cage making it feel like Ochako broke a rib or two. She was flown back into a tree before violently coughing up blood. "What the? You shouldn't have been able to find me in my genjutsu." "When I was reborn, they implanted some anomaly known as a quirk in me to pinpoint the location of someone if I make direct physical contact with them. If you were to attempt this trick earlier in the match, you may have gotten me."

'No, I can't lose here.' Ochako stumbled up having a bit of difficulty breathing before taking two small ninja swords out. 'I guess I have to take my chances going close range.' She charged in channeling lightning into her swords to attempt to slice Neji down. "This won't work for you." He began dodging every slash before hitting her side for the brunette to try to slice off one of his hands to counter. This failed with Neji dislocating Ochako's left shoulder, pulling her off balance, and using a Gentle Fist to her stomach as she to the ground. "ACK!" Ochako had been indented into the dirt before trying to get up with a stumble. "I'm sorry that this had dragged on for so long, but it would appear that even in death, I am forced to serve someone. This time however, I have no choice but to do the wrong thing. Eight Trigaram: Sixty Four Palms!" Neji got into a stance before sending a barrage at ochako.

"Four palms..Eight palms...Sixteen palms....Thirty two palms.....Sixty four palms." The hits sent Ochako right back into a tree breaking it and going into the next tree to only be broken again. By the time she finally stopped, Ochako broke through three trees with the fourth being half broken. Her vision began to become blurry with Neji walking up to her. "It is over. You cannot fight anymore." The brunette looked down to the paper flower that was in her hair before on the ground beside her to remember some of her past. 'Izuku.'

Flash back to age 6

"Run!" Izuku and Ochako began running from Bakugou as him and his lackeys were behind them trying to attack them. Ochako started to trip with Bakugou preparing to attack her. "YOU'RE DEAD ROUND FACE!" She ducked her head preparing for the worst until feeling nothing after the attack made impact with something. She slowly opened her eyes to notice Izuku taking the blast and falling backwards. "Deku!" She ran to him as he fell unconscious due to this attack being more powerful than the ash blonds normal attacks. "What a waste of time. You two aren't even worth it." Bakugou and his goons walked away until Ochako spoke up. "You think you're just gonna do this and walk away!? I don't care who you think you are, you're nothing but a bully!" This comment angered Bakugou for him and his lackeys to gang up on Ochako. "Your funeral round face. DIIEEE!!"

The three began a brutal beating for it to end with Ochako on the ground in pain. The level of personal frustration she had for herself was unbearable. It wasn't the fact she lost a three on one fight with her's and Izuku's tormentor that she was mad about, it was the fact Izuku got hurt protecting her. She couldn't stand this weakness and both respected and envied the greenette for being able to overcome this. If she could, she swore that she'd be strong enough to help her friend even if it would cost her her life.

Back to present

Ochako started getting up with all forms of focus barely managing for her. "I'm not done yet." "Don't try to keep going, or you may die." Ochako started making a few handsigns before taking a breath in. "Fire style: Fireball Jutsu!" She sent the massive ball of flame at the Hyuga clan member for him to toss it back with Rotation. What he didn't see however, was Ochako come barreling through the fireball with one of her blades slicing him across the chest. "This match isn't over, not by a long shot!"

https://youtu.be/zkPZkup8yhY

Ochako kept attacking as fast as she could for each blow to not hit it's mark at all. "You're only prolonging the inevitable. You can barely hit me, what good will going head first into a fight have?" 'He's right, I gotta think up something fast.' Ochako started to see another attack come at her but significantly slower than before. Her eyes started to hurt during this before acknowledging what was happening.

'I can see it!' She deflected and countered the attack with a kick with it being blocked prior to her using her forward momentum to knock the back of Neji's head. "I CAN SEE IT!" Her opponent attempted to retaliate with spinning around to give a Gentle Fist before getting a Kunai in his wrist. To keep from causing problems, Neji jumped back a little to get into the stance he had before. The difference now was Ochako held the same position copying his movements. "Eight Trigram: Sixty four Palms!" Both made attacks at the same spot for their blows to clash with each other with the sixty fourth hit sending both back into a tree. "*cough* I must say, you have shown quite a comeback." Ochako came charging at Neji with her sword infused with lightning again to get a Vacuum Palm to the face. As it impacted however, the brunette turned to smoke showing it was just a Shadow Clone.

"Now where are you?" Ochako came bolting down from a tree above noticing something about Neji's Byakugan. 'It's not a perfect defense. at the back of the neck, there's a blind spot. CHECKMATE!' In one fell swoop, Ochako landed a hit through Neji's heart as he landed a similar hit through Ochako's right lung. "It seems I've won this match." Ochako went pale with a look telling he was right. However, this turned to a smile while she explained how she actually won. "Seems somebody didn't think I'd have a trick or two up my sleeve." Her hands started to pulsate with lighting before it surrounded her and Neji.

(Basically what's happening)

Flashback to the work study

"Today we will be learning how to enhance your Chidori Ochako." "Enhance?" Ochako was quite curious on this since as far as she knew, the Chidori was a completed technique. "Though it is in a way of speaking a complete jutsu, it can still be used differently than it's original state. Take the Rasengan for example. It is far more powerful than the Chidori, but it is still an incomplete jutsu. The rotation power and confinement is just natural chakra and nothing else, where as the Chidori holds lightning in it with the flow of chakra already inside." She thought on this for a while before asking. "So how are we going to do this?" "Think about it for a moment. The Chidori is where you concentrate all the chakra in your hand. What were to happen if you were to do that throughout your whole body?" Ochako realized what her teacher meant while smiling. "Now I get it." "This technique is quite difficult and requires your opponent to be in very close vicinity for it to work. We shall begin training with it right away."

Back to present

"This is the end. Thank you for a hard felt battle Neji Hyuga." The lighting intensified as it went inside the reborn Hyuga's body making his hart convulse and rupture from the puncture it already had. "CHIDORI STREAM!" A massive amount of light was shown where they were to blind everything in the area for a solid minute. When it was over, both fighters were falling backwards with Neji no longer moving or breathing. 'I did it.' Ochako started to cough more blood while looking over to the paper flower Izuku gave her years ago. "Izu...I...won...." She blacked out with a smile on her face knowing it was over at last.

With Momoshiki and bakugou

"At last, it's over." The fluid in the container Bakugou was in drained out with the blond standing up after. "How do you feel?" His curse mark began enveloping his entire body before receding back into it's original form. "Ready to show Deku and those losers who's the real boss in this fight." "Very good. A certain Izuku Midoriya is on his way here. Are you prepared to show him the true power you possess?" Bakugou smirked before answering. "Heh, do you have to ask that?"

And that finishes this chapter. So Izuku is on his way to find Bakugou with the procedure the blond had taken finally ending. See how this turns out next time. Hope you enjoyed and thanks for reading.