A/N: This is something I've had in my head for awhile, and now I've finally gotten it out! Enjoy!
Aizen Sosuke lay painfully on the ground, skin instantly stitching itself back together, relieving the scorching laceration from his back. He heard Kurosaki Ichigo flash step in front of him, mesmerized by the regenerative properties of the Hogyoku. Aizen watched out of mismatched eyes, the flaking of Kurosaki's Final Getsuga Tensho. Ignoring the searing pain, Aizen pushed himself up to stand above the human.
"You've lost, Kurosaki Ichigo. I am now rising far higher than you, who has just lost their very power. Kurosaki Ichigo! You're finished!"
The boy's face contorted in frustration and anger. It soon dissolved into one of fear as a single spike protruded out of his chest.
"What-" Kurosaki began, but several spikes extruding in rapid succession cut him off.
"So it finally activated," a voice noted.
The boy turned around in confusion. Urahara Kisuke strolled onto the scene, weariness etched across his downcast eyes.
"That Kido was hidden within another Kido that was sent into your body just before you achieved a complete transformation, where you had your guard down the most," Urahara explained.
Ichigo continued to stare in shock. Realization finally shown upon his face. Urahara continued to explain, but Kurosaki paid him no mind. Instead, he turned toward Aizen. Blistering fiery erupted in his eyes.
"So, you finally noticed," Aizen commented.
Memories of facing off against Urahara erupted in his mind. The shopkeeper had believed Aizen wouldn't have noticed the extra Kido, and that had been everyone's downfall. For a split second, Aizen had traded places with Kurosaki, and there the Kido went. It was all perfectly timed, for during that moment, Gin had distracted the boy with their own fight.
"Fuck you," Ichigo spat. "Damn you to the deepest pits of Hell! Fuck you, Aizen Sosuke!"
The spikes erupted faster, and Ichigo felt them scraping off his insides, destroying every bit of Reiatsu he had left and sealing them in the pointed spears of light. His fist clenched and his teeth grind against each other. A white flake of skin fell to the ground. Ichigo's fiery lightened slightly, for grim amusement found it's way in.
"Looks like you're losing your power too."
Aizen's eyes widened. Ichigo would have laughed if he wasn't in so much agonizing pain from resisting the effects of the Kido. The boy curled in on himself and watched as the Lord of Las Noches realized he was, indeed, losing his power too. Ichigo laughed morbidly between each labored breath.
"All the power I acquired... is disappearing?" he gasped.
The words of Urahara reached his ears.
"Basically, the Hogyoku no longer sees you as its master."
"Impossible! How can that be!" he screeched to deaf ears.
Out of the corner of his eyes, he saw the spikes instantly shift into crosses. They stuck out of him like arrows, draining what little power Kurosaki had left. He looked back at himself. Beautiful white skin cracked and floated down, and Aizen stared in disbelief. He even sensed his hair receding back into their original length. His Reiatsu dropped down to levels lower than that of a fifth seat. Anger boiled inside of him. Aizen glanced over to the hybrid. The crosses lumped themselves together and speedily crawled up. Kurosaki snarled at him, fury shimmering in the muddied brown orbs.
"Aizen!"
Kurosaki tried desperately to rid himself of the Kido, but it had no effect. The Kido encased him. In a split second, all that was left of the human boy was a star shaped casing. Aizen smirked in victory. Despite his own loss of power, he still had Kyoka Suigetsu. He quickly assumed the role of Kurosaki Ichigo. Soon, he felt human Reiatsu approaching him.
"Kurosaki-kun?" a hesitant voice called out.
Aizen turned his head. Kurosaki's friends stood, completely fear stricken at the mere sight of him. The Kuchiki child and Abarai Renji both smiled, completely unaware of their false reality.
"Where is Kurosaki?" the Quincy bit out.
"Allow me to explain," Aizen smiled.
He got up and walked toward them. They were frozen in place like icicles, each and every one of their eyes were wide in disbelief. He pulled out his Zanpakuto and held it in front of him. They each took a step back.
"Shatter, Kyoka Suigetsu."
In an instant, their eyes clouded over with the current illusion.
"Are you all right?" fake-Ichigo asked in concern.
"I-I thought you were Aizen, but now I can see you're...good...good," Inoue sniffled.
Rukia gave a reassuring smile to Inoue.
"Geez, what a face you're making, Inoue. I know my hair's a mess-"
The orange head fell. Screams of pure torturous pain erupted from the illusion. Aizen watched all of Kurosaki's friends scrambling to the boy. Aizen walked away from the group, for he had another illusion to maintain.
"The judgment will now be decreed! Ex-Fifth Division Captain Aizen Sosuke is sentenced to the lowest underground prison level, the eight prison 'Muken'! For no less than 18,800 years!" boomed Central 46.
Ichigo's eyes were closed. Black, thick bands wrapped around his entire body. The only things left exposed were his left eye and mouth. Now, he had several years to plot and think, presumably in complete isolation. He mentally prepared himself. He heard a door open and close. The Central 46 members continued talking. Ichigo cautiously opened his eyes. Aizen stood, towering over him in his Las Noches uniform.
"What? Came to gloat again?" Ichigo snapped.
Aizen raised his Zanpakuto. Ichigo's eyes narrowed dangerously. Hate radiated off of him, but Aizen paid it no mind. He enjoyed the absolute look of disgust strewn across the boy's features. Aizen may have lost his own power, but it was just a small obstacle in the grand scheme of things. He had no doubts that Ichigo knew it as well.
"No. I came to make sure everything is going as planned. Don't worry, your friends are safe and happy," said Aizen.
"What do you mean?" he hissed.
"Kyoka Suigetsu is truly a magnificent blade. The ability to envelop the world with complete hypnosis is something to be feared. In short, Kurosaki Ichigo, you friends are under my spell."
Aizen saw the apprehensive look in his eyes.
"Don't worry. I won't put you under complete hypnosis. No, I will leave you as the only one who can see past the illusion, forever unable to show others the truth."
Aizen moved to leave as a member of Central 46 ordered Kurosaki's eyes and mouth to be bound. Guards swarmed around the boy. The brunette stared directly into the hybrid's one eye.
"Goodbye, Kurosaki Ichigo, or should I say, Aizen Sosuke?"