In his Shikai state, Aizen couldn't defeat Toshiro, and he wasn't currently willing to reveal his full power. So, for now, the only option was a temporary retreat.
Of course, Aizen could use Kyoka Suigetsu's hypnosis against Toshiro, even though he was unaware Toshiro already had a way to counter it.
But ultimately, Aizen didn't currently intend to truly deal with Toshiro. This battle was merely to understand Toshiro's current true strength, and using such methods would be pointless.
'Well, based on the imposing might Hitsugaya Toshiro displayed upon releasing Bankai, his current strength can be roughly estimated. With that objective achieved, staying here serves no purpose.'
Moreover, the commotion Toshiro caused with his Bankai release even affected the Living World's space. Although Aizen used Kyoka Suigetsu to interfere with the Soul Society's monitoring of the Living World, such a significant disturbance couldn't possibly go unnoticed by the Soul Society.
Thinking this, Aizen decided to leave immediately.
At that moment, Toshiro was already attacking Aizen again.
Seeing this, Aizen immediately activated Kyoka Suigetsu's complete hypnosis ability. While he didn't intend to use it to kill Toshiro, using it to affect Toshiro's perception and seize the chance to leave was no problem.
Immediately, a peculiar glimmer flashed across Aizen's Zanpakuto as he used Kyoka Suigetsu's complete hypnosis on Toshiro, aiming to disrupt his perception and make him unable to see Aizen.
Then, Aizen turned and walked away nonchalantly, ignoring Toshiro.
Unfortunately, Aizen had no idea Toshiro already had a way to counter Kyoka Suigetsu's complete hypnosis.
On the other hand, Toshiro, seeing Aizen suddenly turn his back and walk away so brazenly, seemingly without any defense, was momentarily stunned.
He instinctively suspected Aizen might be setting a trap or plotting something.
But then Toshiro realized: Aizen had just used Kyoka Suigetsu to affect his perception, assuming Toshiro couldn't see him, hence the unguarded departure.
However, Toshiro had been using Dragon's True Eye the entire time and wasn't affected at all.
'A perfect opportunity!!' Toshiro thought. 'Aizen thinks I'm affected by Kyoka Suigetsu and can't see him, so he's completely unguarded. If I launch a surprise attack from behind now, could I kill him in one strike?'
At this thought, Toshiro's heart began racing rapidly.
'But is Aizen really that easy to kill?' He questioned. 'Moreover, if I attack and fail to kill him, Aizen will definitely suspect I might have a way to counter his complete hypnosis...'
Although he had always wanted to kill Aizen, now that a golden opportunity presented itself, Toshiro couldn't help but hesitate.
'Dammit! Do it! I might not get another chance like this!' Decisively, Toshiro chose to act.
Toshiro swiftly swung his Zanpakuto.
Clang! Clang! Clang! Clang! Clang!
Suddenly, countless blades formed of ice appeared in the sky, identical in shape to Toshiro's Hyorinmaru. They rained down on Aizen and the surrounding area like a dense shower of arrows, an all-encompassing, saturation bombardment.
This way, even if Aizen remained unharmed, he couldn't be entirely certain Toshiro had broken Kyoka Suigetsu. He might think Toshiro simply couldn't locate him and was resorting to a wide-area attack, hoping to get lucky.
At that moment, Aizen, who had turned his back to leave, suddenly sensed intense danger approaching from behind.
"Wha-?!" Aizen turned to see countless icy blades descending from the sky like an arrow storm, sealing off the surrounding space, leaving him no room to dodge.
"Bakudo #81, Danku!"
Caught off guard, Aizen had no time to react properly and could only hurriedly cast the defensive Kido, Danku. A transparent barrier instantly appeared before him.
However, this didn't help much. Although Toshiro's attack was dispersed into countless blades, to ensure Aizen's demise, Toshiro had poured most of his Reiatsu into this single strike. So, even divided among many blades, each contained significant power.
Crack! Crack! Crack!
Aizen's Danku barrier developed numerous cracks after just a few impacts, on the verge of shattering.
Boom!
Finally, Aizen's Danku barrier lasted only a moment before crumbling completely. Instantly, Toshiro's countless icy blades engulfed Aizen.
'What's the situation? Is Aizen dead?' Just as Toshiro tried to sense whether Aizen had perished, an overwhelmingly powerful Kenatsu suddenly shot towards him.
Toshiro prepared to dodge but realized the attack wasn't aimed at him.
"Captain!" Following the Kenatsu's trajectory, Toshiro saw its target was Isshin on the ground below.
"Damn it!!" Toshiro completely forgot about Aizen's fate and charged towards Isshin with everything he had. Shunkuho, frost wings… anything that could boost his speed, Toshiro used without hesitation.
At this moment, Toshiro's speed broke through another limit. He finally reached Isshin and Masaki before Aizen's Kenatsu could strike.
With a single sword stroke, Toshiro shattered the incoming Kenatsu.
However, when Toshiro looked back towards Aizen's previous location, Aizen was already gone. Not only Aizen, but Gin and Tosen, who had been hiding nearby, had also vanished.
"I'm sorry, Toshiro. If not for saving me, that mastermind wouldn't have escaped," Isshin said apologetically.
Toshiro reassured him, "Don't worry about it, Captain. It's fine if he escaped. We'll eventually uncover him. And, well... never mind."
What Toshiro didn't say was that even if Aizen hadn't left, he likely couldn't have done much more. Toshiro had launched a surprise attack when Aizen was off guard.
Although he didn't know how Aizen had countered it, the fact Aizen could still retaliate meant he wasn't severely injured. Once the element of surprise was lost, in a direct confrontation where Aizen went all out, Toshiro might not be a match. Then, they would be the ones in trouble.
While Toshiro was confident in his ability to preserve his own life against Aizen, he couldn't guarantee the safety of Isshin and Masaki.
"Alright, Captain, it's time for us to leave too," Toshiro said.