Quick idea I came up with. only a one shot at the moment. Although in the future when I've completed my other stories this might progress into a story of it's own.
There they stood. Two mighty warriors about to engage in combat that would shake the dimensions and decide there outcome. These two beings had similar trains of thought and only one of them knew that but he thought he would keep it a secret for now and show the man before him what he had become. A god.
"Why do you stand there Ichigo Kurosaki? Can you not see that this fight is meaningless?" Sosuke Aizen asked the orange haired teen before him, a calm but serious expression showing on his face. "The world you as you know it is corrupt. The wealthy live healthy lives and drain away the life of the poor creating chaos and madness. Can you not see that? This is the only way as you will come to know."
What did he mean by that? The way he will come to know? It didn't sound right. Aizen was a madman currently dressed in a butterfly wing suit. So why did he say that if he was being so violently oppressed by the man before him.
"Aizen, I cannot allow you to create the Oken, and you are too dangerous to be left alone. Give up while you still can." Ichigo calmly said to the man before him not understanding what the man before him was saying. Perhaps the power had gone to his head.
"If you had lived as long as I have and seen all that can come from living on the streets from day to day you would not be talking as you are now. So I will show you why you will come to know this, and you will agree and do what I have done if you go against me. Tell me do you believe in time travel?" Sosuke continued to speak as the purple orb of the hogyoku continued to shine brightly.
"I said I will defeat you. And now that you are not backing down I will have to finish you off." Ichigo readied his stance slightly his friends looking on in awe as Ichigo faced down this villain before them. Launching off of his feet the obsidian chain wrapped around Ichigo's arm rattled slightly before stopping momentarily as Ichigo appeared in front of Aizen and grabbed hold of his face with his left hand before launching off again into the bare land surrounded by rocky mountains travelling at lightening speeds. Ichigo failed to notice the massive smile that came to Aizens face as they flew through the air towards their destination as though it was all going according to plan.
Suddenly both figures stopped in mid air, Ichigo still grasping Aizen's face with his left hand while Aizen feigned struggling to get out of the tight embrace managing to fool the young by before him. How foolish the young human was. He will soon learn to embrace his true nature.
Ichigo pulled his arm back in a sharp movement before thrusting forwards releasing Aizen causing him to break the sound barrier, clouds of white forming rings around the man as he plummeted towards the ground. As Aizen hit the ground the rocky earth cratered and exploded upwards with the force that the man hit the ground. Just by this simple movement alone he had single handedly reshaped the landscape. Whoever made the maps in the afterlife will have to add the new mark to their map when the battle finishes.
"Hahahaha. Fantastic! Absolutely brilliant!" Aizen roared as he hit the ground, the destruction of the land to loud for Aizen's voice to be heard by Ichigo as he stared on boldly at the monster of a man before him.
"I know that didn't kill you Aizen so come out where I can see you." Ichigo calmly said as his feet touched the ground and stared upon the rubble that Aizen was within.
Suddenly Aizen just appeared in front of Ichigo and made a forward slash that Ichigo just lazily blocked with the black blade in his hand barely putting any effort into his strikes as the earth uprooted itself with every impact that the two made.
To try and get to see a glimpse of how much farther Ichigo's power had come along he thought to taunt the man even though he knew it wouldn't affect him emotionally he knew that he would try and show some of his true power.
"See Kurosaki! With every swing of my blade mountains are destroyed! Even though I did not expect such power yet, you can already see it before you. Give up!" Aizen roared once again as he brought Kyoka Suigetsu around to meet Ichigo's chest and slash through it but was surprised yet extremely excited when the boy caught his blade bare handed. Athough Aizen did not show it he was extremely proud of how far the boy had come. All his work was falling into place. Now the boy just had to convince himself to take matters into his own hand and finish what he started.
Yet again Aizen grinned within his mind at the show of power the boy had given. To keep playing at his little game, Aizen feigned shock and horror causing the man to teleport away and land on what remained of a nearby mountain so he could look down upon the boy as he turned his head slightly to look out of the corner of his eye to see Aizen as he looked down upon the boy that many people had thought to uproot his plans of taking over the soul society and become the spirit king when in fact it only made it all the more feasible.
The boy was good he'd give him that Aizen thought to himself. His mind was developing a in maturity and wisdom at the pace expected. Now all he needed was that final push to send him over the edge and present his most powerful form to him and see if he was worthy of taking on the spirit king.
Aizen's face twisted with what could be assumed anger or simple "You think you're powerful enough to defeat me you human! I'll show you your powerlessness. Seeping crest of turbidity. Arrogant vessel of lunacy! Boil forth and deny! Grow numb and flicker! Disrupt sleep! Crawling queen of iron! Eternally self-destructing doll of mud! Unite! Repulse! Fill with soil and know your own powerlessness. Hado #nintey Kurohitsugi."
The man finished the kido and laughed madly watching as a giant black coffin formed around Ichigo who didn't even bat an eye as to what was about to happen if he stayed there any longer.
"That was the full power of a number ninety hado spell cast by a person who has transcended both hollow and shinigami! The amount of gravity that this spell creates warps even time itself!"
Ichigo simply raised his left hand, the hand that did not hold his blade and swung it outwards shattering the kido that Aizen had encased him in drawing a shocked and strangely pleased look from Aizen as he saw Ichigo bat aside the spell without any former knowledge about kido.
"The blade that destroyed those mountains," Ichigo said coolly as the ground behind him was blasted away by the swing Aizen had made towards Ichigo, "was not yours. It was mine." Ichigo said this all while walking forwards and suddenly lunged at Aizen striking him across the chest and drawing blood easily.
Aizen teleported away yet again although this time because of the wound the boy had inflicted upon him.
"Aizen," Ichigo said looking at the man, "it feels strange. You once asked me why I retreated. Now I am going to ask you the same. Aizen why did you retreat?"
Aizen growled in supposed anger as he looked at Ichigo. "You think you've won just because I retreated?" Aizen said as his wound bubbled with white flesh and he tightened his grip upon the blade in his hand. "Are you pleased that you wounded me?! Do not be so conceited. I will not be defeated by a mere human!"
That was all Aizen said before the white pupil of the third eye showed itself on his forehead and blood dribbled from it. Aizen lost all expression in his face when this happened, his eyes twitched and his heartbeat slowed to a dead stop all for a moment when his head fell sideways. Power burst forth moments later as Aizen roared and a purple reiatsu poured off of him blowing out wind in all directions as Ichigo watched on.
A new set of six heads sprouted from Aizen's back as he screamed consumed by the pillar of energy transforming him once again. When Aizen stopped screaming it looed as though the pillar he was encased in had become solid as it cracked and blood poured out before completely shattering and revealing Aizen's new form.
He had turned almost completely white with the exception of his forearms, hands, feet and head. A hole went through Aizen's midsection, there was another below it as well and another part of his chest seemingly another half done hole housed the hougyoku as it floated within the cavern in his chest. Aizen's face had a black mask and his pupils were no longer visible as only the whites of his eyes showed through it.
"So you will not allow it either will you hougyoku. You will not allow a human to surpass the likes of me." Aizen said as he stood to his full height. When the speech was done Aizen had one of the heads on his wing raise up and gather turquoise energy within its mouth rapidly before firing it at Ichigo who yet again just stood there and took the brunt of the full impact, the miniature nuclear bomb going off and eradicating the landscape yet again.
When the explsion died down it revealed Ichigo still standing there yet with a severely burnt arm shielding his face. Ichigo lowered his arm slowly to his side as Aizen took in all that happedned. The boy was indeed powerful to stand up to the attack.
"I see that even with that attack you are only slightly injured, however that left arm of yours is no longer capable of moving in the state it's in." Aizen said before leaping off of the ground he stood on and into the fire that remained with Ichigo in the centre. He grabbed Ichigo by his neck who seemed to not resist at all as Aizen carried them both out of the fire and stopped once they had cleared some distance and held Ichigo above himself with one arm while the six heads on the wing like appendages surrounded Ichigo on both sides and fed energy into a ring that surrounded Ichigo and gave off a gust of wind that extinguished the fire.
"Can you hear me Kurosaki Ichigo?" Aizen questioned while full knowing that the boy could hear him perfectly. "While you may have temporarily broken the boundary between hollow and shinigami and become a transcendent being you are now a mere shadow of the being you once were havng lost all that power. There is no merit now in even analyzing you any further as you are now. You will meet your death at the hands of the truly transcendent one. By destroying you I will eliminate any further inferior essences of shinigami and hollow. Prepare to die!"
"You think I'll die from this?" Ichigo questioned as he slashed outward with his blades destroying the rings that surrounded him and making Aizen back off of him showing surprise if not only to fool the boy further.
"Hardly." Was the thought that coursed through Aizen's head.
"It's time we finished this Aizen. I'm sick to death…of hearing you talk." Ichigo readied his blade in front of him. "I'll show you. This is the final…getsuga tenshou." Ichigo was instantly covered in bright blue reiatsu and black wisps made their way through it as well.
Aizen watched on in awe as the transformation happened and was impressed by the final form that Ichigo had evolved into. "What is this form?"
When the transformation was near completion the colour of reiatsu had absolutely no blue left in it whatsoever and was completely black. He was covered in gray bandages and black reiatsu constantly fell off of his form making the black hakama he now wore. His hari was also black as his eyes were red.
"This is the final getsuga tenshou. It's when I become getsuga itself." Ichigo revealed to Aizen who's eyes seemed to fill with glee at seeing the form. "When I use this technique I will lose all of my powers."
"Or so you'd think" Aizen thought.
"That is what makes it final." Ichigo said revealing yet even more information to Aizen who was still in thought about the man before him.
"I still can't feel anything from him. He has far surpassed me. All according to plan." Aizen thought as he watched on and prepared for the worst. "When I first evolved into a transcendent being no one could touch me just like a two dimensional being can not interact with a three dimensional being. No soul reaper or human could detect my power unless I brought it down to a level where they could sense me. As I cannot sense him he has passed onto a higher dimension than myself."
Ichigo grasped his hand at his side and a blade of black reiatsu formed there before he brought it overhead and swung downward not giving anytime for Aizen to escape. "Mugetsu." And darkness painted the sky splitting Aizen in half.
When the darkness cleared Ichigo stepped back onto the ground his solid bandages cracking and falling off. Ichigo looked to his left when he heard something hit the ground covered in a dust cloud. When it cleared it revealed Aizen to be regenerating as the flesh along his back stitched the two halves back together. Ichigo flash stepped over to the downed Aizen and was horrified by what he saw. Himself.
"Hehehe, so now you see my true face. I am you Ichigo! Aizen was just a false identity that I used to hide as I worked as a shinigami." Aizen said standing back on shaky feet. "That thing that you called your zanpakuto was a faker and a liar. He prevented your true zanpakuto from surfacing, Kyoka Suigetsu! That man that you hold in so high esteem was the actual reason behind your mother's death, it wasn't me, I would never kill my own mother. His name was Juha Bach, the Quincy king and he fooled you into believing him. Even now he says you have lost your powers when you haven't even used them in the first place! All that power you gained is still right there within your soul." Ichigo said pointing at Ichigo's chest. "Now allow me." Ichigo said as he held an open palm over Ichigo's chest and drew forth a zanpakuto identical to his own and stabbed it in the ground in front of Ichigo as he screamed through the process of having his powers forcibly drawn out.
Ichigo picked up the blade and examined it. It was definitely his. It felt so natural in his grip. Even more so than Zangetsu had.
"How?" Ichigo asked his other self in confusion.
"The Quincy king was ordered by the spirit king to have war with the shinigami all those years ago. It's what caused all the hatred between the two when a solution was already in process to allow the Quincy to purify hollows instead." Aizen said in disgust. "The spirit king slowly over time empowers particular humans that catch the gotei's eye and cause them to wage war killing millions if not bllions of innocents in the process simply because he wishes for entertainment. Now go to the past and fulfill your duty and kill the spirit king." Aizen said swiping his hand forward willing Ichigo into the past.
Ichigo disappeared in a bright flash as red javelins of energy erupted on the older Ichigo's body who just turnedhis head to the man responsible and smiled looking at the shocked look on Urahara Keisuke's shocked face.
"That version of myself is strong Keisuke. He will not have any need for the Hougyoku to kill the spirit king. I know what you did to me and I know that there is no escape. Especially since you are using my own reiatsu to fuel this spell. But good luck with changing the future. His work is sure to affect this world sometime soon as the timelines will clash, merging with each other producing the perfect world!"
Ichigo looked outward and beyond and knew that his other self hadn't moved him from the spot it which he had been standing. If what his other self said was true, then it was time to change the past.