Sakonji Urokodaki did not die in the battle against Upper Rank Three, Akaza, but his life was already nearing its end.
Unlike Tanjuro Kamado, who could survive for one or two more years even after awakening the Demon Slayer Mark, Urokodaki was already old. His body quickly began to fail him.
In the end, he was sent back to Mount Sagiri by the Kakushi to spend his final days.
However, before leaving, Urokodaki spent an entire night in discussion with Tengen Uzui, Gyomei Himejima, and Sanemi Shinazugawa.
Their conversation centered mainly around the Bright Red Nichirin Sword, the Demon Slayer Mark, and the Transparent World.
All of them were Hashira, warriors of the highest caliber. In truth, after learning about the Bright Red Nichirin Sword, the Mark, and the Transparent World, they were already close to being able to wield a Bright Red Nichirin Sword. However, aside from Gyomei Himejima—whose exceptional talent allowed him to maintain it consistently—the others could not sustain the necessary grip strength at all times.
For the remaining Hashira, if they wanted to maintain a Bright Red Nichirin Sword during battle, they would have to awaken the Demon Slayer Mark.
But activating the Mark rapidly drained one's life force, bringing death much closer. That was something none of them could ignore.
From the moment they chose the path of slaying demons, they had never feared death. Yet facing it so directly was never as easy as they had imagined.
So when they saw the Mark awakened on Urokodaki's forehead, each of the Hashira regarded him with deep respect.
Urokodaki described in detail the sensation of awakening the Mark.
To become a Hashira already meant reaching a certain level. After learning the principles behind the Mark, they had already begun to grasp how it could be awakened. With Urokodaki's firsthand explanation, their understanding became even clearer.
Moreover, as they sensed the presence of the Mark on Urokodaki, they all felt a faint resonance within themselves, as if they could awaken their own Marks at any moment.
Just as had been said before, once one marked swordsman appeared, others nearby would begin to awaken theirs as well, as though responding to that resonance.
However, awakening the Mark was not the most urgent matter right now. What mattered more was how to prevent the rapid loss of life that came with it.
After a full night of discussion, they did manage to form some ideas on how to slow down that fatal drain.
As they had suspected, the reason the Mark shortened one's lifespan was that once activated, the body entered a constant "high-temperature" state. Even outside of battle, the heart would beat far faster than normal.
Clearly, this continuous high-speed strain was the root of the life loss. After all, the body's internal organs were far more fragile than one might imagine.
…
Aside from the Mark, Urokodaki also discussed the so-called Transparent World with the Hashira.
He already had some understanding of it, and through their discussions, his comprehension deepened further.
After that night, the Hashira parted ways, each returning to their mission of hunting demons.
As Urokodaki was being escorted back to Mount Sagiri, the last trace of vagueness in his understanding of the Transparent World suddenly became clear in an instant.
Naturally, he stepped into a realm of perfect clarity.
Everything—absolutely everything—was laid bare before his eyes.
Every movement, every detail, was vividly clear.
Even the subtle rhythm of the wind as it passed could be fully perceived.
"So… this is the Transparent World?"
Beneath his tengu mask, Urokodaki lifted his gaze and looked at the Kakushi driving the carriage.
It was not just the man's breathing he could perceive.
He could see the flow of blood through his veins, the rhythm of his heartbeat, the patterns of circulation throughout his body—and even what he would do next.
Everything was unmistakably clear.
He slowly rose to his feet and looked around.
The wind, the sand, the grass, the trees—everything was astonishingly clear, as though the entire world lay within his grasp.
The world itself had not changed, yet what he saw, what he felt through his breathing, what he heard with his ears—everything was completely different. If before it had been like looking at flowers through a veil of mist, then now… it was as if he could see through all things, like a god who understood everything.
…
When word spread that Sakonji Urokodaki had returned, everyone gathered early at the foot of Mount Sagiri to wait for him.
The happiest among them was undoubtedly Makomo. She had already guessed what her teacher intended to do. She had thought it would be a farewell—perhaps they might meet again someday, but that meeting would likely belong to another world, forever separated.
Yet she had never expected that her teacher would return unharmed.
That alone filled her with overwhelming joy.
Soma also felt a sense of relief. After all, he had developed a genuine bond with Urokodaki during their time together on the mountain.
However, he knew that even if Urokodaki hadn't awakened the Mark to fight Akaza and exhausted his remaining life, the old man wouldn't have lived much longer anyway.
Unless—
he could somehow achieve what Tanjiro Kamado would in the future: finding a way to awaken the Mark without suffering the loss of lifespan.
But that possibility was far too slim.
Since the Mark was first awakened by Yoriichi Tsugikuni, only he—and later Tanjiro—had been able to reach that state. No one else had ever succeeded.
Soma did not believe that Urokodaki could achieve it.
…
In the distance, the carriage soon arrived. Makomo practically rushed forward with joy, helping her beloved teacher down.
The old man looked even weaker than before. He could barely step down without Makomo's support.
And yet, there was something about him—
an indescribable presence.
Soma had been feeling pleased, but the moment he sensed that aura, he suddenly froze in place.
That feeling—
that presence, like something akin to a plant, something utterly still yet alive—
he had felt it before.
It was the same sensation he had experienced that snowy night, when he first faced Tanjuro Kamado. That same quiet, almost plant-like aura.
"The Transparent World…"
Soma understood it instantly.
He knew the level Urokodaki had reached.
For a brief moment, he almost turned and left without hesitation. But in the end, he remained where he stood, silent and still.
Being able to see his disciple Makomo again brought Urokodaki great joy. To return to Mount Sagiri in the final stretch of his life, to rest in this familiar place—it filled him with deep comfort.
Yet even that could not compare to the exhilaration he felt from stepping into the Transparent World at the end of his life.
The moment he reached that state, he had already written down his understanding of it, intending to share it with Soma later.
What Soma had shown during this time made Urokodaki see hope—hope for eradicating demons—and he wished to pass on everything he had learned.
So as Makomo supported him, Urokodaki felt a rare sense of excitement.
However—
when he saw Soma standing in the distance…
the eyes beneath his tengu mask froze for the very first time.
The scent he detected—the scent of a demon—was almost identical to what he had sensed the first time they met. Back then, seeing Soma standing under the sunlight, he had thought his nose was mistaken.
But now—
having stepped into the Transparent World, he could see it clearly.
The one standing before him…
perhaps…
could no longer be called human.
And yet—
why was he able to stand beneath the sunlight?