Ichigo gasped and sat up. There it was again! That freakish spiritual pressure! He suddenly grimaced as his wounds started opening up.
"Kurosaki-san, I told you have to not move while I healing your wounds," Unohana calmly said, and started to re-patch some of the wounds Ichigo had opened.
"Yes but... what was that spiritual pressure? Surely you felt it too?"
"...Yes, that was Urahara-san." Unohana blandly stated, then started to heal Ichigo's left shoulder, which had been slashed open by Aizen.
Ichigo couldn't believe his ears. He knew Urahara was an ex-captain, but that spiritual pressure was far out of a captains league. And it was different. Very different.
"...Unohana-taichou? What is Urahara-san?"
The captain in question sighed, and looked up into the deep, blue sky. "It's a very long story..."
"Is that it, Aizen? Is that your limit? If so, that is rather disappointing," Urahara said, sounding almost bored.
The scene was shocking to say the least. Aizen, in less than a minute of fighting Urahara, had been lowered to one knee, was panting heavily, and had dozens of small cuts all over his body, and a large gash in his side.
"I see. Well that certainly surprised me. To think you were one of the infamous demonic angels," Aizen said, wiping the blood off his face.
"Well I am surprised even you know about us Aizen," Urahara replied. "I thought we hide our existence pretty well."
"You do, and were it not for the fact that one of your people came and offered his services to me, I would still be ignorant of you," Aizen said.
"Oh? And who is that?"
"Gin, of course."
"Ah, that makes sense. That also explains why he always has his eyes closed," Urahara sighed, and then locked eyes with Aizen.
"As for your previous question, yes and no, Urahara Kisuke," Aizen said, breathing heavily. "Yes because that last attack exhausted me, and I am clearly at my limit currently. However, you are also incorrect, because," he smirked, "I have not even drawn my bankai yet." He then lifted up his sword and called, "Seal!"
All of a sudden orange reiatsu flooded out from Aizen, and even though both of them were in the air, the ground which was directly below Aizen began to shake and crumble almost seemingly of its own free will, and then started to crack across its surface. The cracks then spread across the whole area of Karakura, and after about half a minute, it stopped. Suddenly, the cracks all glowed orange, and from a bird's eye view the cracks appeared to be a giant skull. Suddenly the ground started to cave in on itself, and swallowed up Karakura town.
"What?" Urahara exclaimed, watching as all the shinigami, visoreds and hollows were swallowed up and the ground vanished with them, and all that was left was him, Aizen and the sky.
"You see, that last attack of yours was a powerful one, and combined with that little surprise you had for me, you were able to push me to use my bankai. However, it is over for you now." Aizen said, before charging at Urahara with blinding speed. Urahara however drew his sword, and he parried Aizen's blade, and then thrust back at him. Aizen carelessly blocked Urahara's thrust then drove his sword down to slice his opponent in two. Urahara dodged the chop, and stepped back for a second, before charging back into the fray.
The two continued to exchange blows and the sound of clashing metal resounded all around the empty sky. That's when it hit Urahara. Of course! That cheeky bastard has got me trapped inside some sort of sealing device, like a bubble. Humph! If this is his amazing "bankai" then that is a pretty pathetic bankai. Once I have defeated Aizen, I can then think about finding a way to get out of this bubble. Plan ready, Urahara decided maybe unnerving Aizen would be a good start.
"Well your bankai is certainly unique, but from what I can tell, it seems rather pathetic. I mean, from what I can tell, sealing someone is good and all, but how does that help you defeat them?"
Aizen looked startled for a moment. How did he figure out my bankai was a sealing device? As expected of Urahara Kisuke. He is probably the only person in the world that could compare to me intellectually. Still, he missed one crucial detail...
Aizen then replaced his startled expression with a smug one. "Aren't you forgetting something rather important?"
What does he mean? Urahara thought. Wait, how was it that I was able to see Karakura being destroyed in this "bubble"? Don't tell me...
"It seems, by your shocked expression that you have realised it. Yes, my bankai has two abilities: one is to seal the owner and another person inside a closed space. Second is that while both people are in the seal, the owner can create any illusion, without any boundaries or limits to plague the minds of the second person. As for destroying the seal, the only way to do it is for the owner to either destroy the seal of his/hear free will, or for the second person to kill the owner. I am sure by now you understand the implications of the situation: The only way for you to escape is to kill me, but that will be impossible because my illusions will prevent you from even touching me. In other words, I am unbeatable," Aizen explained, finishing his final statement with a triumphant smile.
.