Sextuple Bankai

***Author Note***

Well, sorry for the long period of silence, but this damn chapter has been kicking my ass for the last few weeks. By now, I rewrote this one like five times, and frankly, I'm still not entirely satisfied with it.

Anyway, instead of rewriting this another thousand times, I decided to just post it now and get it over with.

***End of Author Note***

""""""Ban-KAI!""""""

Six outrageously powerful Spiritual Pressures exploded outward, mixing together and confronting each other as six of the most powerful Bankai in the history of Soul Society were unleashed simultaneously, causing the air to stir and the space to tremble.

"[Zanka no Tachi]"

Instead of everything burning even brighter, Yamamoto's flames completely vanished, while what appeared to be a charred glowing Zanpakuto was the only thing that might indicate his current state.

During his Bankai, all his flames were concentrated at the tip of his sword, resulting in it becoming outrageously hot, allowing it to destroy everything it touched. Usually, it would get so hot that everything around him would be ready to collapse, however...

"[Ten-Tailed Heavenly Demon Fox's Shape, Goddess of Ice's Divine Regalia]"

Unlike Yamamoto's Bankai, which concentrated all its power into a single point, Yuna's area of influence was spread even further, while the innate ability of her ice to devour everything became even stronger.

The dangerous part of Yuna's ice was never its coldness but its ability to freeze everything, so even if the disparity between the temperature Yamamoto's blade created and the one Yuna's did was vast, her ice was still slowly covering everything, as snow started gently falling from the sky.

"[Minazuki]"

As ice and fire were fighting for dominance, blood started flooding the battlefield, Yuna's ice freezing it, while Yamamoto's blade turned it into mist, resulting in a balance, allowing Retsu to use her ability freely.

"[Grand Ocean Domain]"

Just like Retsu's Bankai, which created a lot of blood, Hinata's Bankai activated, creating an Ocean of water, flooding the battlefield and intermixing with Retsu's blood, thinning it out while simultaneously increasing the ground it covered and reducing the impact of Yamamoto's Bankai even further.

"[ASURA]!!!"

Madness and battle thirst filled the battlefield as Kenpachi consciously activated his Bankai for the first time while even calling out its name, turning his blade into a massive cleaver while making him look like a demon. Although nothing in the environment changed, his dense killing intent and Spiritual Power alone managed to put pressure on everyone else.

"[Ten-Tailed Wind Demon Fox]"

Finally, Naruto's Bankai caused multiple powerful tornados to spawn, which mixed the effect of all the currently active Bankais together, causing the situation to get even more chaotic.

Seeing the chaos that happened due to the activation of multiple powerful Bankais, Yamamoto couldn't help but observe the situation with fascination.

So far, whenever he was forced to activate his Bankai, it was basically a race for time, as it was only a matter of time until the power of his Bankai destroyed everything around him. However, now that was no longer the case as multiple other Bankai of similar power were activated, balancing each other out.

'What overwhelming power. Obviously, I was aware just what kind of power Captain Unohana and Captain Kenpachi's Bankai would have, but it's truly fascinating that these three humans can actually match the power of our combined Bankais. It seems that Yuna claiming that I could use my Bankai without worries was the truth. How inconceivable.'

Seeing Yamamoto's expression, which was a combination of excitement and bewilderment, Yuna couldn't help but smile herself as she raised her sword and pointed it at Yamamoto.

"I hope you are ready, old man."

The moment Yuna stopped speaking, she vanished from her position and appeared in front of Yamamoto, who managed to see through her movement and instantly slashed his sword at Yuna, who allowed her own blade to contact Yamamoto's, resulting in the two opposite forces to repel each other.

However, seeing that his blade didn't obliterate Yuna's, Yamamoto couldn't help but be surprised, as there was usually nothing that could withstand contact with Yamamoto's blade while his Bankai was activated.

Well, the heat of his blade actually DID damage Yuna's sword to some extent, but unfortunately for him, that didn't matter as the damage regenerated instantly.

After all, just how often has Yuna created her ice sword in her life? A million times? Ten million times? For her, recreating her sword from scratch was easier than breathing, so repairing it was something that didn't even need to be mentioned.

While the duo was repeatedly clashing, Hinata appeared behind Yamamoto, ready to hit him from the back, but before she could do so, Retsu intercepted her attack, allowing Hinata's blade to pierce through her hand while using her other to slash at Hinata. After all, getting wounded was no problem for Retsu, as she would regenerate instantly anyway.

"Sorry, but I have already seen your assassination style."

Seeing Retsu's sword approaching her and hearing her words, Hinata hummed in acknowledgment as a wall of water rose between her and Retsu, blocking the attack.

"Geez, I feel like my assassinations have been failing rather frequently in recent times. Although I admit that I'm not exactly aiming at easy targets, it still is a little annoying. Guess I'll have to increase my training~"

The thought of Hinata getting even better at assassinating people terrified Retsu a little, but despite that, she kept a smile on her face as blood continued dripping from her sword. Moments later, she slashed her blade dozens of times within an instant, causing a mass of flying blood slashes to fly at Hinata, who countered the move by simply controlling the water she was standing on to shoot a dense beam of water at every single one of these slashes.

"HAHAHA, AS EXPECTED, YOU ARE A MONSTER JUST LIKE YOUR SISTER!!!"

Meanwhile, Naruto was facing Kenpachi, who was going absolutely insane as he slashed his massive blade at Naruto like a madman, producing massive gashes in the ground every time he swung his blade. This was the first time Kenpachi was fully conscious while using his Bankai and feeling the power coursing through his body; he loved every second of it.

Usually, he didn't like having too much power, as that would usually end in an easy victory and a boring fight, but now things were different, as despite him feeling almost invincible, his opponent still could match him.

Feeling the ungodly amount of Spiritual Power flooding his body, Kenpachi had no doubt that if he were to face other people he had bester before, more than 99% of them would die instantly. Despite that, he was currently trading blows with a human not even in his twenties. Obviously, he didn't care about the age gap in the slightest and only enjoyed the fight to his fullest, discarding every other aspect of this fight as useless.

Naruto, on the other hand, couldn't help but smile as well. It has been a while since he fought someone like Kenpachi. Usually, the stronger an opponent gets, and the more they age, the more tactical combat would become, as the berserk types usually tended to die early.

However, Kenpachi was clearly someone who just fought as his instincts told him to, and funnily enough, that was exactly what Naruto preferred to do as well.

So, as Naruto's knuckle dusters blocked yet another swing of Kenpachi while Naruto's ten tails moved in an attempt to stab Kenpachi, the impact of the confrontation caused the duo to slide backward, creating distance between the fighting duo, causing Naruto to smile.

"Man... it's been a while since I fought someone like you. Well, Ichigo a moment ago was somewhat similar, but that was different. Hehe, you don't mind if I rampage a little, do you, Kenpachi?"

Hearing Naruto's words, Kenpachi frowned as he readied his blade. Although he didn't know what Naruto meant by rampaging a little, he could only interpret it as putting more effort into the fight, making him smile.

"Hee, so you are still not giving it your all? Come, show me what you can really do. You better not die before I have enough fun to satisfy me."

"Fun to satisfy you? What a joke. I'm not here to entertain you! You are here to entertain ME!!!"

As soon as Naruto stopped speaking, his facial expression changed, as it became more feral, while the whiskers on his face grew more pronounced, and one of his usually blue eyes became red.

["It's been a while since I got a chance to stretch my legs, so I might as well have some fun, right~"]

"[Hehe, that's right, Kurama. Let's have some fun together~]"

Although Kenpachi felt a little weird that Naruto suddenly started talking to himself, with a weird voice that sounded like two people talking simultaneously, he never let his guard down, allowing him to see Naruto's attack that happened just after he stopped speaking with himself.

Meanwhile, Ichigo, Isshin, and Aizen, who were facing each other, had not exchanged a single blow as the trio's eyes were firmly fixed on the apocalyptic battle not too far away from them.

'What the hell is this!? How are these three so strong!? Didn't we become Shinigami more or less at the same time!? Why do all three of them surpass me by such a huge margin.'

Seeing the battle in the distance, a mix of emotions flooded Ichigo's body, ranging all the way from terror due to the insane amount of Spiritual Pressure the distant conflict produced all the way to annoyance due to him being surpassed by the trio by such a huge margin.

'I really wonder what has happened since I left Seireitei.'

While Ichigo was flooded with uncertainty, Aizen had several questions, as well. First of all, why did Kenpachi suddenly not only have a Shikai but even a Bankai, while his Spiritual Pressure had multiplied as well? Next, he really wanted to know when Retsu's personality had reverted to what it once was in the past.

Then, of course, there was Yamamoto, whose Bankai Aizen had only heard about and never seen, and what he had heard about it apparently was completely wrong.

'Damn, did someone feed me false information deliberately, or did something change with his Bankai? If he had used that before Wonderweiss could seal his flames, I would have been in a lot of trouble.'

And finally, the most important and profound question Aizen REALLY wanted someone to answer him was the following: What the f*ck!?

'I knew Yuna was strong... Well, I didn't from the start, but the more she showed off what she could do, the clearer a picture I could draw about her strength... Or that was at least what I assumed to be the case, but it seems I was completely wrong.'

Aizen had again and again adjusted how strong Yuna was in his mind, and his final estimate placed her somewhere along the ranks of the stronger Captains. Now, however, Aizen had no other choice but to toss that estimation out of the window, as that "ranks of the stronger Captains" individual was currently trading blows with the Head Captain going all out. Strength of a strong Captain? What a joke! The Head Captain could easily one-shot such individuals with his Bankai!

'What makes it even worse is that she isn't even the only one with such outrageous strength, as somehow, there were two more humans that could fight at almost the same level.

'If someone told me a few hours ago that I would witness three human brats not even in their twenties fighting the Head Captain, the previous Kenpachi, and the current Kenpachi, I would have probably laughed into that person's face.'

However, here it was! Right in front of him! A scene Aizen couldn't even imagine would happen one day was happening right in front of his face.

Meanwhile, Isshin wasn't entirely sure how to react to what he was witnessing either. He was pretty sure that Yuna knew about his identity as a Shinigami, as he had appeared in front of her brother before. Isshin had rarely met her, but when they did for the first time, he noticed her briefly glancing at the way he moved before checking his hip, clearly looking for a sword. He didn't really get it at that point in time, but now he was pretty sure that Yuna figured out that he could use a sword from the way he moved, terrifying him a little.

Putting that aside, Isshin had always had trouble reading not only Yuna's intention but what her two comrades were thinking as well. All three of them were a mystery to Isshin.

Obviously, he had also heard a thing or two about Yuna and her little group of monsters from Kisuke, but now that everything was revealed, it became clear just how much everyone had underestimated those three.

Getting out of his daze, Isshin's eyes landed on Aizen, who was spellbound by the monstrous fight as well, while seeming deep in thought, causing Ishhin to smile.

'Well, let's see if this will work out~'

So, while Aizen was still deep in thought and no one was paying attention to him, he sneaked up on Aizen and raised his Zanpakuto.

"[Getsuga Tensho]"

Obviously, Isshin was aware that yelling the attack's name out loudly was exactly a prime example of stealth; however, words held power, and using the attack's proper name would inevitably reinforce its form and increase its power.

Hearing those two words, Aizen's eyes widened as his gaze landed on Ichigo, who was startled by the yell as well. Seeing that Ichigo wasn't the one attacking him, Aizen instantly realized what was going on and spun around just in time to barely block the sneak attack.

"Tch, I was hoping I could strike in while you were in a daze."

Kurosaki Isshin, huh? I fear it won't be that easy to beat me."

"Yeah, figured that out already."