Itachi suddenly appears behind Gin, aiming a slash for his head. Gin's eyes open, revealing his sharp light blue eyes as he moved his head bȧrėly in time, only receiving a cut on his cheek. Gin backs aways from Itachi with a flash step and wipes the blood dripping down his cheek.
"Even when you're not at full strength, your speed is impressive." Gin commented. Gin raised his sword and pointed it at Itachi.
"Bankai, Kamishini no Yari."
In an instant, Gin's zanpakuto extended. Itachi narrowly dodged the blade as it went past his face, destroying several buildings behind him.
"Oh you managed to react to that too?" Gin said as he raised his now retracted sword up again. Gin pointed his sword at Itachi again as it extended.
Itachi quickly flash steps out of the way of the blade and appears in front of Gin. With his blade, Itachi slashes at Gin, only for his slash to be blocked by Gin's retracted blade.
"Do you know how long my blade can extend?" Gin asked as he and Itachi clashed swords. "Thirteen Kilometers."
Itachi remained silent and continued slashing at Gin, keeping him on the defensive.
"Oh so you think keeping this close to me will keep me from extending my Zanpakuto?" Gin commented as his blade suddenly expanded as he swung, cutting through Itachi's body and the buildings behind it. Suddenly Itachi reappeared behind Gin, causing Gin to retract his blade and block his attack.
"Darn I was sure I got you. But you had me with that afterimage. I shouldn't have expected anything less from someone who was in the Stealth Corps. But no matter how far you run, my zanpakuto will-"
"Your zanpakuto's ability doesn't lie in its length or speed…" Itachi interrupted. "Your zanpakuto turns into dust the moment before it retracts, leaving a portion of itself in whatever it hits. I ȧssume the portion it leaves behind is lethal, acting as a poison of some sort."
Gin's smile turned into a frown upon hearing Itachi's summary and he quickly backed away. His smile quickly returned though as a bright red tip of a sword appeared behind Itachi. Itachi turned around and saw that even Yamamoto had fallen for having to resort to use a kido like that.
'So that's Itto Kaso...Hado 96…' Itachi thought to himself.
"Man...you're perceptive. How did you find out about that." Gin laughed as he sheathed his blade again. "Anyway it seems Aizen is done with his battle. I enjoyed our fight, Uchiha."
As Gin finished his sentence, Aizen suddenly appeared in front of him. Itachi and Aizen locked eyes as Aizen grinned.
"Your illusions won't work on me, Uchiha. It is simply the will of the Hogyoku, my will, that prevents them from doing so." Aizen said as he tore open his shirt, revealing the Hogyoku implanted into his ċhėst.
"Aizen!!!!" An angry voice yelled from behind him. Harribel suddenly appeared behind Aizen, with her blade aiming for his head. Without turning around, Aizen swung his zanpakuto, cutting through Harribel's blade and across Harribel's body. As her body lay on the floor, Aizen turned around and picked her up by the neck.
"I have no room for weaklings or traitors in my Espada." Aizen said coldly as he tightened his grip, causing her to cough up blood. As Aizen continued choking Harribel, he suddenly felt a large increase of reiatsu appear next to him as a giant ethereal blade headed towards him. He quickly let go of Harribel and jumped back, losing his arm in the process. As he turned to face what had struck him, he saw a giant armored form surrounding Itachi.
---------------------------------------------------
"Impressive. You managed to cut me." Aizen complimented as he picked up his dislodged arm and reattached it to his body, his wound instantaneously regenerating.
"But as you can see, I have reached a form far beyond what you could hope to-" Aizen stopped talking as he sensed a massive reiatsu behind him. Both Itachi and Gin turned their attention to the space behind Aizen as a crack began to form in the air. Suddenly, a familiar orange haired young boy burst out, his eyes filled with rage.
"Kurosaki?!" Itachi exclaimed, his normally stoic demeanor broken as he both saw and sensed Ichigo's reiatsu. It was far greater than it was when he had last seen him in the human world. His physical appearance had also changed, His hair was now longer, flowing down to his back, and half of a mask covered his right eye, with a strange horn sticking out.
"Getsuga Tensho!"
Aizen's body was suddenly covered by a dense black reiatsu that shot across the entire town, splitting it in half. Itachi watched silently and observed Ichigo's new form as Gin quickly backed away.
As the smoke cleared out from the blast, Aizen's figure was revealed, with nearly half of his body completely vaporized by the attack. Aizen grunted and coughed up blood as he fell to one knee and laughed.
His laughs were cut short though, as a giant orange blade pierced through his body, before he had time to process what was going on.
'The Totsuka blade... can't absorb him?!' Itachi thought, surprised that Aizen's body was still holding on. 'The Hogyoku, it's keeping my Blade from absorbing him!'
Suddenly, Aizen's power began to grow and his body let out a bright light that filled the area as the force of his reiatsu pushed everything back from around him. Itachi's Susanoo began to wither as he tried to hold the Totsuka Blade on Aizen, but it was too much, resulting in him being sent flying back.
As the bright light disappeared, Aizen's body was revealed to have changed. His white sclera were now purple and his hair longer, with a single strand that went down his face that reached his shoulder.
"Kurosaki Ichigo. What an interesting power you possess. You have far surpassed my expectations." Aizen said as he began walking to Ichigo whose eyes were filled with rage.
"Don't give me that shit Aizen! How dare you do that to Nel!"