Staring at the mysterious figure before him, Shinji's expression flickered with uncertainty.
Soul extraction was undoubtedly more convenient and efficient than the back-and-forth of genjutsu interrogation, but its sheer efficiency caused Shinji to absorb an overwhelming amount of information, forcing him to carefully sort through it.
Naturally, the first thing he sifted through was the mysterious figure's information regarding the invasion of the shinobi world.
Through directly reading memories at the soul level, Shinji finally learned the mysterious figure's true name: Ryūhei Ubuyashiki.
Born into the Ubuyashiki clan, he earned the title of "Lampbearer" from a young age and, with the aid of the "Lamp," trained in the "Breathing Techniques," gradually becoming one of the strongest warriors in the Demon Slayer Corps.
As his strength grew and he explored the abilities of the "Lamp," Ryūhei Ubuyashiki grew dissatisfied with the limitations of a swordsman's "Breathing Techniques." He began using the "Lamp" to traverse different worlds, collecting more powerful abilities.
At first, perhaps due to caution or sheer luck, his travels across several worlds went smoothly. Not only did he befriend other "Lampbearers" from those worlds, but through trade, he also acquired numerous abilities and items from them.
This allowed his strength to surpass the limits of a Demon Slayer Corps swordsman, making him a formidable warrior who exceeded even the legendary strongest swordsman, Yorichi Tsugikuni!
With a powerful weapon in hand, a killing intent arose!
Having reached the pinnacle of his world, Ryūhei Ubuyashiki began his hunt for demons!
As a "Lampbearer" who had traversed multiple worlds, his perspective was far beyond that of an ordinary Demon Slayer Corps member.
He understood clearly that demons were both a calamity and a treasure in his world.
Thus, while hunting demons, he coveted their terrifying regenerative abilities and long lifespans, leading him to conduct cruel experiments on them!
As his research deepened, he gradually realized that "demons" represented the true ceiling of power in the Demon Slayer world.
The creation of demons might have been a mere coincidence, an accident.
But their existence undeniably elevated the power level of the Demon Slayer world, pushing it firmly into the realm of the extraordinary.
Compared to demons, who had virtually no lifespan limits and could grow indefinitely, the swordsmen who practiced "Breathing Techniques"—with their limited lifespans and vulnerability to injuries—were far too fragile.
Even Ryūhei Ubuyashiki himself, or the legendary creator of the "Breathing Techniques," Yorichi Tsugikuni, could not escape the shackles of aging, weakening with time and ultimately succumbing to death!
The thought that he, a noble "Lampbearer," would die of old age while even the lowliest, ant-like demon could easily live for centuries filled Ryūhei Ubuyashiki with unbearable resentment.
Thus, he made a decision: to abandon his identity as a Demon Slayer Corps swordsman, to abandon his humanity, and to become a demon!
Driven by ambition and unwillingness, he quickly tracked down the Demon King, Muzan Kibutsuji.
Using his shared lineage with Muzan, he brutally seized the Demon King's power, erased Muzan's memories, and successfully stole the Demon King's strength, becoming the new Demon King!
After becoming a demon, Ryūhei Ubuyashiki's power skyrocketed.
He mastered both the demonic power of blood and flesh and the swordsman's "Breathing Techniques" to their utmost limits, becoming the strongest existence in the Demon Slayer world. To ensure no one from his clan could strip him of his Demon King power, he secretly exterminated the Ubuyashiki clan, becoming the last living member of his bloodline!
Having accomplished all this, Ryūhei Ubuyashiki's strength surpassed that of many "Lampbearers" from other worlds. No longer cautious in his travels, he resorted to killing and plundering without restraint to further enhance his power!
But karma eventually caught up with him. While plundering a world, he caught the attention of a Hegemon who had also set their sights on that same world.
Greedy, he didn't retreat immediately. Instead, he sought to harvest more lives to boost his strength before the Hegemon could consume the world.
Unbeknownst to him, the Hegemon had already infiltrated every facet of that world. By harvesting its lives, Ryūhei absorbed the Hegemon's power, allowing the Hegemon to track him down through that power after devouring the world. The Hegemon then set its sights on the Demon Slayer world.
A world targeted by a Hegemon had only one fate!
After experiencing fear and despair, Ryūhei devised a plan: to pollute another world, luring the Hegemon to a world near the Demon Slayer world, thereby shifting its attention and delaying the destruction of his own world.
To achieve this, two conditions had to be met.
First, the other world's power level had to surpass that of the Demon Slayer world, ensuring the Hegemon's attention would shift.
Second, the "Lampbearer" of that world had to be eliminated in advance to prevent them from using the "Lamp" to counter him or drag the Demon Slayer world down with them.
This was the reason Ryūhei Ubuyashiki invaded the shinobi world. He sought a "sacrificial pawn" to take the Demon Slayer world's place as the Hegemon's meal! He chose the shinobi world because its power level was higher, making it more "appetizing" in the Hegemon's eyes.
"Disgust!"
That was Shinji's blunt assessment of Ryūhei Ubuyashiki.
Not only did Ryūhei bring calamity upon his own world for selfish reasons, but he also schemed to sacrifice other worlds to save himself.
According to the information Shinji extracted from Ryūhei's mind, even if the Hegemon's attention was temporarily diverted to another world, it would eventually return to consume the Demon Slayer world after finishing the other.
In other words, even if Ryūhei's plan succeeded and the shinobi world became the "sacrificial pawn," it would only buy a brief reprieve. Once the Hegemon devoured the shinobi world, it would turn back to the Demon Slayer world.
Shinji glared at Ryūhei Ubuyashiki with icy eyes. "Killing you would be letting you off too easily!"
Even tearing Ryūhei apart piece by piece wouldn't quell Shinji's rage. However, perhaps because Ryūhei was once a "Lampbearer," Shinji couldn't find detailed techniques for using the "Lamp" or traversing worlds in his soul.
Thus, Shinji decided to awaken Ryūhei Ubuyashiki for interrogation before finishing him off.
But just as Shinji roused Ryūhei, a steady sound of footsteps echoed from nearby.
Shinji and the newly awakened Ryūhei turned to look. Instantly, Ryūhei's face twisted in horror. "You—"