Inside the quiet laboratory.
Aizen stood before a table, looking at the sword embryo that had already undergone some changes, with a hint of anticipation in his eyes.
At this moment, the surface of the pure white sword embryo was already covered with slightly strange black patterns, scattered like clouds across the blade.
This was the result of him erasing Ido's will and injecting that abnormal Chakra, capable of interfering with reality, into the god tree factor sword embryo through sealing techniques.
The entire process took about a month.
However, the contemplation and preparation before this had lasted for several years.
Now, he had just found a suitable piece of the puzzle.
However, although these patterns still possessed a unique aesthetic, they did not align with Aizen's initial idea.
"It must be that this energy reacted in some as-yet-unknown way with the god tree factor during the injection process."
"Or even... some kind of evolution?"
Aizen repeatedly pondered the connection between the god tree factor and Chakra, then felt that something seemed off.
"Rather than saying this energy is similar to Yin Release Chakra, it's more like a special kind of natural energy—one that cannot be absorbed by the human body."
"It has Yin Release characteristics, yet it's also like natural energy?"
"Then, what is the connection between natural energy and Chakra?"
Untested theories could only remain theories. Perhaps Aizen would try to find their conversion relationship in the future, but at least not now.
Aizen temporarily set aside these thoughts, reached out, and took the cloud-patterned sword embryo into his hand.
First, he carefully felt it for a while, then cautiously injected Chakra into it.
The sky-blue Chakra flowed in little by little, entering without any hindrance, quickly illuminating every cloud pattern, emitting a faint warmth in his palm.
Just as he had initially envisioned.
The sword embryo, constructed entirely from the god tree factor, possessed an extraordinary adaptability to Chakra.
Almost the moment he injected Chakra, the sword embryo formed a complete 'connection' with him, as if it had directly penetrated his soul.
No, not just 'as if'.
Aizen seemed to perceive something, a faint light flashing in his eyes, as he gazed at the sword embryo lying across his hand and tentatively increased the Chakra output.
Indeed.
Just like a true Zanpakuto, as he increased the Chakra input, the sword embryo itself also grew in size and changed shape, gradually transforming into the appearance he desired.
For Shinigami, each person's Zanpakuto is a manifestation of their spiritual body and total spiritual power.
If a captain-level Shinigami wished, he could even expand his Zanpakuto to the size of a building.
It would just become quite fragile.
Not only that.
Aizen tentatively raised his fingertip.
Without any hand signs, a faint, flickering light spontaneously ignited at his fingertip.
Just now, he had directly interfered with the flow of Chakra with his soul.
This was the phenomenon that resulted.
"Not only can it interfere with the Zanpakuto itself, but it can also directly interfere with reality in the form of a soul?"
Aizen was somewhat surprised.
Although he had initially taken Ido's soul fragment precisely for its 'interference with reality' characteristic.
However, being able to transfer this characteristic so perfectly to this sword embryo greatly exceeded his expectations.
It seemed the god tree factor's adaptability to energy was far better than he had imagined.
"If that's the case..."
As if thinking of something, Aizen turned his head to look at a white mouse trapped in a test tank, then suddenly raised his hand.
"Binding Spell One: Restrain."
Almost the instant his two fingers pointed out, the white mouse, which had been lively and scurrying around in the test tank, was suddenly frozen in place by an invisible hand, struggling with difficulty.
In a flash, it then burst into a splatter of blood with a 'pop'.
Aizen frowned slightly.
Just now, he had chosen to use the sword embryo in his hand as a soul amplifier, attempting to discard the interference of Chakra and use Kidō with the power of his soul, as he had in his previous life.
But the result was obvious.
The moment he used even a little spiritual power, Chakra, like a persistent parasite, immediately surged out in the direction of his will, following this reality-interfering characteristic, and disrupted the Kidō's circuit.
This caused a slight deviation in the force.
However, as he pondered, Aizen's frown gradually relaxed.
Whether it was Chakra or spiritual power, both were essentially energy.
Since the Kidō of his previous life couldn't adapt, he just needed to modify the Kidō's circuit.
This way, he would have another means at his disposal.
If low-level Kidō was fine, then what about higher-level ones?
Aizen thought, and began to chant softly:
"O, ruler! Mask of flesh and blood, all creation, flapping wings, you who bear the name of man! Scorching heat and strife, surging backward across the seas, march forth!"
"Destructive Spell Thirty-One: Red Fire Cannon!"
He completed the incantation, raising his hand forward.
However, the dark red ball of light that appeared in his palm only maintained its flickering form for an instant before suddenly collapsing and dissipating.
Aizen was startled.
With his soul level and experience, releasing Kidō of this caliber under full incantation conditions should never result in failure.
It wasn't until he felt it carefully that he looked at the sword embryo in his hand.
"So that's it."
He finally understood.
If his soul were compared to a lake, then Ido's characteristic of possessing the power to interfere with reality was like a filtering water pipe.
The phenomena appearing in reality were the pure water filtered through the screen.
Trying to draw out the entire lake's water through a pipe in one go was clearly an absurd thing to do.
"It still needs further refinement."
Aizen shook his head, but he wasn't particularly disheartened.
During the initial development of the Hōgyoku, he had encountered far more failures than he had now.
It wasn't until after many more experiments that Aizen determined that, by suppressing himself, he could probably complete Kidō up to about number ten.
Although the number was small and the power relatively limited, it at least gave him a few small tricks that could surprise ordinary people.
Though this achievement was minor, it allowed him to perceive some connection between natural energy and Chakra, as well as a peculiar conversion relationship within it, which was a small gain.
However, he still needed to put in some effort regarding the modification of Kidō.
Just as Aizen was contemplating potential breakthroughs, the laboratory door was suddenly knocked.
"Come in."
When the door opened, Hyuga Hizashi was seen kneeling, saying in a deep voice:
"Lord Aizen."
"Large-scale chaos has begun to appear within the Uchiha Clan Compound."
He had previously instructed him to report certain specific phenomena when observed.
"It has already begun."
"I thought Shisui-kun could hide for a bit longer."
Aizen said, first fastening the sword embryo to his side, then turning to take a letter from another desk and handing it to Hizashi:
"Please help me deliver a letter."
"Just give it to Itachi-kun."
Hyuga Hizashi bowed deeply, without the slightest hesitation:
"Yes."
Aizen maintained a gentle smile, quietly watching Hyuga Hizashi's retreating back.
It was about time to cast the net.
Itachi-kun.
I hope you truly possess enough capacity.