This feeling wasn't unfamiliar to Gojo Yoru.
Before sudden death, the body gives warnings.
If you've been pushing yourself with too many late nights, sometimes you can't sleep at all—instead you get more and more wired, your mouth goes dry, your temperature rises.
Even worse, your heart starts racing. That panicky, tight-chested sensation makes you afraid that if you fall asleep, you might never wake up again.
Yoru had experienced this plenty of times in his previous life. He was young then and never took it seriously.
But now that the same sensation had come back, fear surged through him.
Without hesitating for even a second, Yoru got up to drink water—careful not to gulp it down, only taking small sips.
When the dryness eased a little, he carried the kettle back to his room, lay down again, and tried to empty his mind and calm his heartbeat.
But no matter what he did, his heart rate didn't slow down even a bit.
In the dead silence of the night, his room sounded like someone was beating a drum.
He lifted his shirt. His chest was pumping so violently it felt like he could see the heart inside, like it wanted to burst out of him.
His overstimulated mind, the waves of rising heat, and the recurring dryness made sleep impossible. All he could do was keep boiling water and drinking.
He even took several cold showers, but nothing eased it.
And the situation still hadn't disappeared by noon the next day.
Not counting a half-hour nap yesterday, Yoru had gone a full thirty hours without sleep.
Yet he didn't feel miserable at all.
In his previous life, staying awake that long—even if he felt hyped—his nerves would be taut, his eyes bloodshot, sometimes even inflamed.
But in this life, he had none of that.
Once he calmed down, he realized his energy was absurdly abundant, like a perpetual-motion machine.
Obviously, it was the effect of his heart pumping like crazy.
That state lasted for a full seven days.
Yoru also went without sleep for seven days—nearly two hundred hours without closing his eyes.
What's more, during those seven days, he didn't eat a single thing—only drank huge amounts of water.
It wasn't that he didn't want to eat. He simply couldn't.
The weird part was: seven days without food, and his body didn't change at all. He was still overflowing with energy.
Yoru's emotions gradually shifted—from fear to excitement.
If this were truly sudden death, someone who hadn't slept for seven days would've been dead long ago.
But he hadn't died. Which meant it wasn't sudden death—his body was undergoing some unknown transformation.
Maybe… his cheat was finally arriving.
Was it some unknown Gojo-family bloodline limit awakening in his generation?
Or some special ability that had come over from his previous life with him—maybe even the real reason he'd transmigrated in the first place?
That "sudden-death" sensation didn't fade until noon on August 28, Konoha Year 30, when it finally began to disappear.
"It's finally—"
The moment his heartbeat returned to a normal rhythm, the low-fever warmth and dry-mouth sensation vanished. He hadn't even finished his sigh of relief or checked for changes when his vision suddenly went black. He collapsed onto the bed and fell into a heavy, roaring sleep.
He had no idea how long he slept—until the hunger, sharp enough to churn stomach acid, yanked him out of deep sleep.
"So tired…"
Yoru opened his eyes, but he didn't want to get up at all.
It had been a long time since he'd felt the exhausting heaviness of not having enough sleep.
If the ceiling and his surroundings weren't there to remind him, he would've thought the last six years had been nothing but a long dream.
He rolled onto his side, pulled open the bedside drawer, and took out a box. Inside were two rows of six pellets—compressed rations and "mana recovery" medicine in the Naruto world: soldier pills.
One wasn't enough. Yoru ate three soldier pills before his hollowed-out body recovered a bit of strength.
He got out of bed and went to a full-length mirror. Stripping off his clothes, he turned in a circle, inspecting himself. When he saw no visible changes, he immediately sat cross-legged and began refining chakra—checking whether anything inside had changed.
Thump—
A sound like a war drum exploded beside his ears—inside his head—deep in his soul.
In that instant, his gaze seemed to turn inward, as if he'd gained internal vision, arriving in the "room" where the heart sat inside the body.
In that "room," there was a black heart—beating thump-thump.
The image flashed and vanished.
Yoru snapped his eyes open, stunned.
If he hadn't misseen it… that heart looked… black?
"Don't tell me that's my heart?!" he thought.
To confirm, Yoru closed his eyes again and continued refining chakra.
But the internal-vision scene never appeared again.
Instead, right as physical energy and spiritual energy were about to fuse, a strange third energy suddenly surged out from his cells and forcefully joined the fusion.
And then a thread of black chakra, formed from the fusion of three energies, appeared in Yoru's abdomen.
"Black chakra… is this my cheat?"
Yoru opened his eyes again, formed hand seals, and tried to mobilize that thread of black chakra.
The black chakra didn't seem all that different from normal chakra. Pulled by the hand seals, it flowed through his chakra pathways and reached his right palm.
Maybe the amount was too small, or maybe his chakra control still wasn't good enough—the black chakra didn't manifest outside his body.
And in only a few seconds, that thread of black chakra disappeared back into him.
In that short time, Yoru couldn't find anything special about it.
So he closed his eyes again and kept refining chakra.
The strange energy surged again, mixing with physical and spiritual energy to form thread after thread of black chakra.
When Yoru could no longer draw physical and spiritual energy from his cells, that strange energy went straight for the main "nest," merging into the blue chakra vortex inside him.
Like ink seeping into white paper, part of his chakra slowly shifted from blue to black.
By the time he could no longer extract that special energy at all, fully one-third of the chakra in his body had turned black.
"Alright. Let me see what you actually do!"
Yoru stood up, hands forming seals—excited, yet nervous—mobilizing the black chakra as he began to perform a technique.
Ever since he refined his first thread of chakra at age three, Yoru had already gained a basic grasp of the academy's Three Basic Techniques. During this vacation, he had also begun training C-rank elemental ninjutsu.
He couldn't use elemental techniques at home, so he decided to test the black chakra with the Three Basic Techniques instead.
The result was… nothing happened at all.
No illusion clone formed. His body didn't change shape in the slightest…
Instead of being disappointed, Yoru felt delighted.
If he couldn't use techniques with it, that meant this black chakra was different from normal chakra. It wasn't that he'd discovered a flaw—only that its "special effect" was buried deeper.
And mystery meant… power.
Yoru swallowed another soldier pill, opened the balcony's glass door, and looked out at the dim, brightening sky. Hands forming seals, he prepared to dash out like an afterimage.
Then he paused.
He remembered he'd successfully moved the black chakra into his palms earlier. So he redirected the black chakra down into his feet, preparing to use the Leaf Body Flicker—something even the academy taught, a D-rank technique.
Just like when he tried the Three Basic Techniques, Yoru didn't vanish into an afterimage.
But he felt something underfoot—like stepping into empty air.
He looked down, and his pupils shrank violently.
His feet looked like they were sinking into a swamp—his lower legs had actually submerged into the balcony floor.
But he didn't feel squeezing or pressure. His body didn't keep sinking. It was as if his feet weren't "stuck" in the balcony at all, but fused with it.
Yoru slowly lifted his leg and pulled his right foot out of the balcony.
Staring at the floor—no dents, no damage—Yoru finally lost control of his expression. He lowered his head, covered his face with both hands, shoulders trembling, letting out a sound that was either a sob… or laughter forced down so hard it came out as a shaky hum.
Only after a long while did he drop his hands and look up.
Konoha, bathed in morning glow, looked so beautiful it felt like a painted scroll—as if he were seeing the village he'd lived in for six years for the first time.
His mouth was still stretched into a grin. He spread his arms and laughed as he exclaimed:
"What a beautiful village. What a… wonderful world!"