(3rd Person POV)
Ichigo and Toji were going at it in the training chamber. Toji had to upgrade it over the days and make sure that the high Reishi didn't leak outside and attract every single spiritual being in the universe. He also made it stronger since Ichigo was finally getting to the stage where he was unconsciously using not only his strength alone but his Hollow/Zanpakuto as well.
Those two were always connected anyway. His inner hollow WAS his Zanpakuto and his Shinigami powers. So it was important for him to use it fully and not be afraid of that. The fear part was already resolved in the first two weeks of the training. Ichigo could fight against Zangetsu and had gained a big boost in his instincts. He was no longer afraid of the powers inside him.
"Very good Ichigo!", Toji said after he blocked an attack from him. He was increasing his strength and skill constantly as soon as Ichigo adapted to it and also grew more powerful and skilled. He wanted to have constant pressure on Ichigo. Something that forced him to combine his strength with Zangetsu.
And it worked wonderfully. He didn't even notice but for the last day, he had been fighting with Toji nonstop and had his Hollow 'mask' on the entire time.
He said mask but that was no longer the correct description. It was more than that. It was beginning to grow from the normal round face mask, that only covered his face, to something that covered more than just his face. The beginnings of a horn were seen as well, telling Toji that Ichigo was beginning to tap into his power that was hidden by 'Yhwach-Zangetsu'.
For some reason ... Toji was immensely proud of the progress Ichigo had made in honing his skills as a Shinigami and refining the determination and resilience that defined his journey as the one who protected everyone he cared about.
.
.
As they were fighting Toji felt something ... he prepared to finish the session for now with one final attack to test his progress.
He blocked Ichigo's swing with his bokken and then focused on something. He brought his finger up and ...
Just as he was about to attack ... Ichigo retreated far back. Toji smiled at this but went through with the attack anyway. He brought his finger down and a big slash was seen that seemingly split the entire chamber in two.
"Haha, very good Ichigo. That was marvellous indeed. I am happy with your progress these past four weeks and can now-", Toji was saying but the pressure he sensed before it came, was now spreading over Karakura Town.
Ichigo felt it too. His eyes widened and the mask that held on for so long finally shattered. There it was again. The mental state that was not yet there where Toji wanted it to be. Not much was missing. He knew that it was soon where he wanted it to be.
"Grimmjow...", Ichigo said and then Shunpo'ed away.
"Wait ... *sigh* ... no matter the talent or power ... he is and stays a 15-year-old. But that's ok, I guess. He'll do what needs to be done anyway. I'll see how things go now that I have trained him. Although he should have let me treat him first. We have been fighting non-stop for an entire day. He's going to be exhausted."
.
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A Garganta opened above the park in Karakura Town to reveal Yammy, Grimmjow, Luppi Antenor, and Wonderweiss. They are here for ... well who knows? Shortly after they arrive, Captain Hitsugaya attacks Yammi, the 10th Espada, while Ikkaku and Yumichika try to fight Luppi.
Ichigo arrives at the scene and confronts Grimmjow.
"Hey. I've been looking for you, Shinigami.", Grimmjow greets Ichigo.
"That's my line. I'll show you ... how much I've changed in the past month!", Ichigo answers him.
"Ban k-"
"Now hold up a second there Ichigo.", the voice of Toji is heard from the side. Ichigo stops his activation and looks at his teacher.
"Sensei ... why did you stop me?", Ichigo asks.
"You are not to use your Bankai against the jaguar and you are also not to use your mask either. I want to see your improvements this past month and see whether I didn't waste my time.", Toji tells him.
"What?! But-"
"No excuses. If you can defeat him without your Bankai or using your mask, I will give you a gift.", Toji tells him.
"Alright. Let's do this ... Grimmjow."
"Your Bankai didn't do anything against me, last time! So you think you can beat me without it? You must be delusional to think that.", the Espada said arrogantly. Then he looked at Toji and looked displeased.
"And who is that? Is he here to make sure you don't die?"
"No ... you can be glad that you don't have to fight against him. Now come on, let's do this.", Ichigo says and attacks Grimmjow.
.
On the other side, Luppi was manhandling both Yumichika and Ikkaku and challenged both Rangiku and Hitsugaya to a one-on-four fight. Hitsugaya tried to stop Luppi from releasing his Resurrección and attacked him ... or her with his Bankai.
He was however denied an easy win, as Luppi managed to go into Resurrección and attack him. Hitsugaya was pushed away and then attacked with 7 more tentacles by Luppi, which took him out of the fight for the moment.
"What a disappointment the current Gotei 13 are ...", Toji said as he watched Hitsugaya get defeated in one attack. Rangiku, Yumichika and Ikkaku tried to hold their own against the new Espada number 6. And surprisingly it was Rangiku who did the best. She did as well as Hitsugaya did, which goes to show how strong she could be when she had her full soul and some training from Toji.
But it also goes to show how much talent she wasted over the years and now was paying the price as she stood there bloodied and out of breath just like the other two.
"This is pathetic.", Luppi said, "Are you guys really 13 Court Guard Squads officers? So boring. The woman at least has something going for her. But my that is embarrassing."
The three attacked again and tried to do ... something. Anything really but that was not likely going to happen.
.
In the distance, Yammi was sitting and watching the fight happen. He was terribly bored right now and was too lazy to go look for other prey ... that was until he saw Toji just standing there and watching the fight between the tired Ichigo and Grimmjow.
He was just about to attack Toji when he felt something. Something that felt like a giant sword aimed at his neck ... he couldn't see anything but he experienced a chilling feeling running down his back, as Toji looked at him from the corner of his eye. The silent promise of death was felt by Yammy and he didn't go there.
.
With Luppi and the other three, he was looking at the three he had caught with his tentacles. He spoke to Rangiku.
"Lady, you've got a hot body. I'm jealous. You're so sexy.", Luppi said. He then transformed one of his tentacles into a spiky variant and had it face Rangiku.
"Maybe I'll punch you full of holes."
The spiky tentacle shot towards Rangiku but she was no longer looking like she did before. She had a serious look on her face. She narrowed her eyes and then said the release for her Zanapakuto.
"Growl, Haineko."
At that moment a lot of ash began to appear and cover Rangiku, protecting her from the spikes. But that was not all. The ash continued to increase in amount and spread all around the tentacles and Luppi. His sight was diminished greatly and he could no longer see anything. And then ... hundreds of thousands of cuts appeared on his entire body.
"ARRRGGHHH"
Luppi screamed at the damage that Rangiku inflicted on him with her Shikai alone. But that wasn't all. She was far from the same weak, drinking Lieutenant that she was in the story. The ash continued to increase in density and slowly seeped into the wounds that had been made due to her Haineko.
It was a very cruel and gruesome technique that she initially didn't want to learn but Toji made her do it anyway. He said that if she ever wanted to grow powerful enough to catch up to Gin, she would have to get into the right mindset. So Rangiku began to develop the technique that Toji dubbed 'Infiltration'.
It did just what it said. Rangiku injected small amounts of Reiatsu into her enemies by cutting them with her ash. These wounds would then serve as 'landing platforms' for the ash that was Haineko and allow her ash to 'infiltrate' the enemy's body. The more ash that got into the body of her enemy, the better control she would gain over his or her body.
In an attempt to create a killing move, Toji helped her come up with the move they called 'the Volcanic eruption'. It did literally what it said again. Like a volcano, all the ash that had entered the person's body, ignited and made the person explode.
There was another thing that Toji told Rangiku, she should work on and she managed to do it. Since the beginning of his new life, Toji has been very focused on expanding his imagination. He spent a lot of time, dreaming and going over new things to imagine and try out. That is also the reason why he asked himself what the limits are to a specific Zanpakuto.
He thought about Byakuya Kuchiki. His Shikai at the beginning of the series consisted of 1000 blades that were seen as Sakura petals. But in the Thousand Year Blood War arc. this number increased so much that his Shikai appeared to be his Bankai, which were stated to be in the millions. So what was the limit to a Zanpakuto?
So after thinking about it, Toji told Rangiku to try and have the enemies whom she uses her move 'Volcanic eruption' on, turn to ash and then collect all that ash and implement it into her Haineko. That would result in her gaining more ash than she used and therefore ... theoretically, making her Zanpakuto more powerful and have more ash.
She said that Haineko wasn't happy about that, but saw the benefits and tried to do it. Apparently, it was like trying to fit more water into an already full bowl. They did make it, but only very slowly. That is why she had more the three times her original amounts of ash.
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Together with Toji, Rangiku would try out more and more techniques of her Zanpakuto and even managed to ignite her ash at one point. That is also how the technique 'Volcanic eruption' came to be possible.
Rangiku's Reiatsu was also Captain level. It was interesting for Toji to see what she could do if she hadn't lost part of her soul in the original. He trained her in Zanjutsu and also how to use her Zanpakuto smartly. He had already met Haineko many times and even though he and her wished that Rangiku would begin Bankai training, she never showed any interest.
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As Luppi was cut all over his body and screamed, Rangiku didn't stop there. There was only one man who could look at her with these eyes ... even though he never did ... otherwise, she found it disgusting and would get very violent.
She used 'Infiltration' on Luppi and began to pump him full of ash ... that sounded wrong. But as the Arrancar was filled with ash, he experienced the worst pain imaginable. He tried to scream but his lungs and all the muscles around him weren't under his control any longer.
"No one looks at me like that ...", Rangiku says with a low and slightly menacing voice ... something that we're not used to from her. Clearly, she learned from Toji.
"You shouldn't have done that. 'Volcanic eruption!'"
Rangiku's voice was heard all around the area and in a terrible explosion, the Arrancar number 6 was killed and the ash that his corpse became, was added to Haineko like a trophy.
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We see a change that the MC brought to the story. The ones he trained are truly stronger than they were in the original. And we also see what 'could have been', if Aizen hadn't taken a part of Rangiku's soul.