What shocked Rangiku even more was that within this Reiatsu, she not only sensed Shinigami's Reiatsu but also Hollow's Reiatsu.
It was as if this Hollow wasn't formed from the corruption of an ordinary person, but from the fall of a Shinigami.
But how was that possible?
Generally speaking, Shinigami's Reiatsu and Hollow's Reiatsu simply couldn't coexist within the same living being.
After ordinary people in the living world die, most are guided to the Soul Society by Shinigami. Those with Reiryoku might enter the Seireitei to become Shinigami.
Souls with Reiryoku that aren't promptly guided to the Soul Society and still hold attachments to the living world will gradually be consumed by those attachments and turn into Hollows.
Hollows killed by Shinigami's power have their souls purified and re-enter the cycle of Reishi.
So how could a Shinigami have Hollow's Reiatsu?
'No!'
'It does exist!'
Just as Rangiku was inwardly astonished, a flash of insight suddenly crossed her mind.
'The Shinigami Hollowfication Experiment!'
Over seventy years ago, a malicious incident occurred in the Seireitei.
The former 12th Division's Captain, Urahara Kisuke, abused his position to conduct Shinigami Hollowfication Experiments.
At that time, a total of four Captains, one Vice Kido Chief, and two Lieutenants became victims of the Hollowfication Experiment.
Afterwards, 2nd Division's Captain, Yoruichi forcibly broke into the Central 46 and rescued the main culprit Kisuke and the Grand Kido Chief, Tsukabishi Tessai, who had used forbidden Space-Time Kido.
That was the most severe blow the Gotei 13 had suffered in a thousand years, losing six Captains at once.
And from Kyoya, Rangiku learned that the incident back then wasn't so simple.
According to Kyoya, behind Kisuke, there was a deeper, hidden mastermind, one that even Kisuke probably hadn't detected.
Kisuke did indeed conduct Hollowfication Experiments, but he didn't use Gotei 13's Shinigami as experimental material.
The fact that Kisuke and the others left the Soul Society didn't mean the Seireitei was safe.
'Now, this Hollow, which clearly possessed Reiatsu exceeding that of an ordinary Captain, was it the work of the mastermind hidden behind Urahara Kisuke, the one who caused the Hollowfication of several Captains?'
"Rangiku, I'll go ahead. Be careful!"
Sensing that the Hollow was rapidly approaching other people, Isshin instructed Rangiku behind him, then burst forth with his Reiatsu, transforming into a white streak flying into the distance.
"Wait, Captain Shiba-"
Hearing Isshin's words, Rangiku was startled and wanted to tell him her suspicions.
But unfortunately, Isshin had already flown far away and couldn't hear what she was saying.
'No...'
'This matter… I need to tell Gin...'
'No, I should tell Kyoya!'
At first, Rangiku did want to tell Gin.
But she remembered what Kyoya had told her before, and her current suspicions.
Rangiku suspected that Gin might be following Kyoya's orders, infiltrating the mastermind's side.
If she sent a message to Gin, it might expose him and put him in danger.
Immediately, Rangiku summoned a Hell Butterfly and stored the message she wanted to convey within it.
"Go."
Watching the Hell Butterfly fly away, Rangiku's expression turned serious.
With a 'boom', she also released her Reiatsu and quickly flew towards the direction where Isshin and the Hollow were fighting.
"Stop-"
When Isshin saw the Hollow killing people, he was furious. Raising his Zanpakuto high, white Reiatsu spread across his blade-
"Getsuga… Tensho!"
A crescent-shaped slash over three meters long flew out, its target precisely the Hollow that was attacking its next victim.
If it continued forward, it would inevitably be hit by this slash.
"Tch-"
The Hollow ultimately stopped its movement, allowing the slash released by Isshin to pass in front of it, carving a long trench in the ground.
"Whoosh!"
Seizing this opportunity, Isshin used Shunpo to move in front of the Hollow, protecting the person who was almost devoured behind him.
"It's dangerous here. You should leave first."
"Ah, ahhhhhh..."
Only then did the people, scared to the point of tears and snot streaming down their faces, begin to let out miserable screams, scrambling to flee in all directions.
Whoosh-
Whoosh!
Clang!
Clang!
Clang, clang, clang, clang-
Figures flickered. Isshin and the Hollow became two afterimages, chasing and fighting each other on the ground.
Every time the two collided, sparks would burst forth in the night, then disappear.
'This guy is so strong!'
Isshin was inwardly shocked.
From the Reiatsu alone, Isshin could sense that this suddenly appearing Hollow was definitely a Vasto Lorde-class Menos Grande.
However, this Hollow's fighting style, in Isshin's view, was vastly different from other Hollows.
On the contrary, while fighting this Hollow, Isshin felt like he wasn't fighting a Hollow, but another Captain-level Shinigami!
Furthermore, unlike other bizarrely shaped Hollows, the Hollow before him was a standard humanoid Hollow.
Apart from the mask on its face and the two black and white horns on its forehead, this Hollow had no other non-human features.
Fortunately, Isshin's own strength wasn't weak. Even without releasing his Zanpakuto, he still managed to suppress the Hollow.
"Captain Aizen, would you consider this one a success or also a failure?"
In the sky above where Isshin and White were fighting, Aizen, Gin, and Tosen stood in mid-air, watching the battle between Isshin and White below.
The one asking was, naturally, Gin.
Tosen was Aizen's loyal follower. As long as it was Aizen's order, Tosen wouldn't question the purpose, only blindly execute the command.
Only Gin would ask Aizen, attempting to find Aizen's weaknesses from any clues.
"Ah, it should barely count as a successful experiment, I suppose!"
Aizen smiled.
The Hollow below was one he successfully created using the power of the half Hogyoku in his possession, collecting the souls of many Shinigami to create a 'Hollow' possessing Shinigami's power.
From its birth, it possessed the highest level of Vasto Lorde-class Reiatsu.
Additionally, this Hollow also possessed the combat instincts of a Shinigami.
Even though it was at a disadvantage against Isshin, Aizen didn't consider it a failure.
After all, this Hollow had just been born and hadn't been trained yet.
Presumably, after a few more battles, it would inevitably improve further.
"It's about time for the next phase of testing."
Hearing Aizen Sousuke's words, Gin narrowed his eyes and asked as if casually, "Next phase of testing? Are you going to make this thing fight against two Captain-level powerhouses?"
Currently, the closest to the battle site between Isshin and White was naturally the rapidly approaching Rangiku.
Gin asked this precisely to clarify Aizen's goal.
If Aizen dared to involve Rangiku, even though he hadn't yet figured out Aizen's weakness, his blade was not necessarily dull!
"Two Captains?"
Tosen frowned. Beneath his purple eyepatch, one could only see his brow furrow and the corners of his mouth turn down, expressing his confusion.
"Captain Aizen, according to my senses, only the 10th Division's Lieutenant Matsumoto is rapidly approaching here."
"To use two Captains to test this thing, do you need me to intervene?"
"No, you misunderstand, Kaname."
Aizen shook his head: "What Gin meant by two Captains wasn't that we need your help, but that Lieutenant Matsumoto also possesses Captain-level strength!"
"How is that possible?"
Tosen exclaimed.
"That woman actually possesses Captain-level strength?"
His words, though full of doubt, showed he wouldn't question Aizen's statement.
What surprised him was that Gin actually knew Rangiku possessed Captain-level strength, while he himself needed Aizen to point it out.
"Kaname, you mustn't forget, Lieutenant Matsumoto is that person's family."
With just one sentence, Aizen made Tosen realize where the gap between himself and Gin lay.
Everything he knew about Kyoya came from descriptions by other Captains or Shinigami under his command.
Gin, however, had been a Lieutenant under Kyoya for over ten years.
If not for that, Gin's strength wouldn't have surpassed his, making him Aizen's new right-hand man.
"After all, it was just born. Having it deal with Captain Shiba is already difficult enough."
"If we add Lieutenant Matsumoto, this thing won't last long."
"Let's relocate the battlefield for now!"
Unlike Isshin, who could match White without releasing his Zanpakuto, Rangiku's strength wasn't sufficient for her to fight a Vasto Lorde-class Menos Grande in her base state.
If Rangiku were to release her Zanpakuto later, the three of them hiding in the air might even be affected.
...
Boom!
Whoosh, whoosh, whoosh-
Isshin blocked White's attack with his sword, forced back by the powerful force, his feet carving two trails on the ground.
But at the same time, Isshin also sensed what his enemy intended to do.
"Don't think you can escape!"
Seeing the Hollow in front of him open a Garganta, Isshin shouted, released his Reiatsu, halted his retreat, and rushed rapidly towards White.
But unfortunately, Isshin was a step too slow.
By the time he reached the Garganta, White had already slipped inside.
"Too bad, it got away..."
Isshin said regretfully.
This Hollow was definitely the strongest one he had encountered in many years.
Moreover, Isshin could feel that during their battle, this Hollow's combat experience was rapidly increasing.
'No!'
'Not that its combat experience was rapidly increasing.'
'Rather, it felt as if it inherently possessed strong combat experience or instincts, and was merely activating those experiences or instincts during the fight with me.'
'It was foreseeable that if we met again, this guy would be several times more troublesome than now.'
Just as Isshin was sheathing his Zanpakuto, preparing to return to his division, he suddenly noticed that the aura coming from this Garganta wasn't the empty aura of Hueco Mundo, but instead a place with numerous chaotic auras.
This feeling was somewhat similar to the auras of the residents in the Rukongai.
'Could it be that there were ordinary people in Hueco Mundo?'
'No!'
As the Captain of the 10th Division, Isshin quickly realized.
The destination of the Garganta opened by the Hollow that had just fought him and escaped wasn't Hueco Mundo, but the living world!
"This guy!"
Isshin looked at the rapidly shrinking Garganta before him. Without time to think, he directly leaped into the Garganta.
He needed to enter the living world through the Dangai opened by this Garganta before it closed.
Otherwise, not only would the Shinigami stationed in this city in the living world be killed by this Hollow, but possibly all the people in this city would be devoured by it!
Although it's said that Vasto Lorde is the endpoint of Hollow evolution, as Menos Grande that reach the Vasto-Lorde level no longer need to devour souls to sustain their existence, nor do they fear degenerating into mindless Gillians like the Adjuchas, Isshin could feel that the Vasto Lorde-class Menos Grande he fought was a 'monster' with only combat instincts.
In the Seireitei, this guy couldn't control its 'devouring' desire, or rather, it simply couldn't be bothered to control its 'devouring' desire.
Now entering the living world, wouldn't it treat the ordinary people there as meals?
For every second he was late, many people might be injured or even killed.
"Captain Shiba!"
When Rangiku arrived, she saw Isshin enter the Garganta without saying a word, her expression changing immediately.
But unfortunately, by the time she reached the Garganta's location, it had completely closed.
Immediately, Rangiku didn't dare delay and began chanting a Kido's incantation.
"Heart of the south, eye of the north, finger of the west, foot of the east, arrive with the wind and depart with the rain."
"Bakudo #58, Kakushitsuijaku!"
Rangiku pressed her hands down, white Reiatsu spread from the ground, allowing her perception to extend, capturing the Reiatsu of the Gotei 13's Captains and Lieutenants.
"Silken net of black and white! Twenty-two bridges, sixty-six crowning sash…"
"Footprints, distant thunder, pointed peaks, revolving grounds, nightly prostrations, sea of clouds, the pale ranks of troops…"
"Complete the grand circle and surpass the heavens."
"Bakudo #77, Tenteikura!"
Numerous Captains and Lieutenants connected by Rangiku's Reiatsu looked up at that moment.
Even those who were asleep immediately got out of bed and began dressing.
Any message that required the Tenteikura to transmit was no small matter.
Sure enough, as they expected, Rangiku's next words made the Captains and Lieutenants of the Gotei 13 immediately head towards the 1st Division.