Amidst the swirling, golden arc light, Ren stood like a statue in the eye of a storm. He took a long, steady breath, bracing his soul to accept the torrent of new energy that was about to surge through his meridians.
In an instant, Ren felt his consciousness plunge into a world of blinding flashes and rolling thunder. It wasn't just a mental shift; it was a physical coup. He could feel his very blood, the lifeforce that had once flowed sluggishly through his veins suddenly strike a rhythm like a war drum. Struck by the "lightning" of the system's reward, his blood began to surge with a violent, erratic pulse, dancing through his arteries like liquid fire.
Ren's body began to vibrate. It was a subtle, high-frequency tremor, like a piano wire plucked with impossible strength. Each vibration was a refinement, peeling away the "silk" of his previous limitations to reveal the steel beneath. A web of golden light, a literal thunder net, broke through his skin, illuminating the courtyard. The light leaked from his eyes, his mouth, and even his pores, making him look less like a man and more like a celestial being descending to earth.
By the time the fusion ended, Ren's muscles felt dense and resilient, and his bones felt as though they had been forged in the heart of a lightning strike. He exhaled a long, thin stream of white vapor.
"Thunder Breathing, Second Form... Rice Spirit!"
As the words left his lips, the pent-up energy within Ren exploded like triggered dynamite. It raced through his meridians, converging on his practice blade with such force that the air around the wood began to distort and shimmer.
Ren's feet shifted, a movement so light it barely disturbed the dust and he vanished. In the space of a heartbeat, he had closed the distance to Gramps. The sword, wreathed in snarling golden electricity, descended with a roar that shook the very foundation of the wooden house.
Gramps, the former Thunder Hashira, didn't panic. With the instinct of a seasoned warrior, he pivoted, his wooden cane catching the light as he narrowly dodged the first overhead strike. But Ren didn't stop. The "Rice Spirit" was a flurry, not a single blow. Four more consecutive strikes followed in a jagged, circular pattern, each one leaving a scorched trail in the air.
Gramps danced through the lightning, his movements a blur of practiced grace. Despite the speed of the attack, the old man remained untouched, though his expression was one of absolute, unadulterated astonishment.
Ren came to a halt, his chest heaving. Using two forms consecutively, especially at high intensity, was a massive drain on his current stamina.
"Ren... your epiphany..." Gramps' voice was uncharacteristically shaky.
He had thought Ren's mastery of the First Form was an incredible stroke of luck, a rare talent finally blooming. But this? The Second Form was a complex, multi-directional attack that required perfect synchronization of the breath and the blade. Ren's execution wasn't just "good", it was equal to Gramps' own. He had spent decades perfecting these forms; could a boy truly rival his mastery in a single night of "clarity"?
Gramps glanced down at his sleeve. There, on the fine fabric of his kimono, was a small, blackened scorch mark. His heart skipped a beat. If Ren had been just a fraction faster, or if his own reflexes had been a second slower, that strike would have drawn blood. He was nearly cut by a boy who, yesterday, couldn't even stand in a proper stance.
[Ding!]
[Detected that Jigoro Kuwajima's friendship level has increased to 'Close Friend'.]
[You have received a random reward!]
[Acquired: Skill: Total Concentration Breathing: Constant (Mastery)]
[Would you like to merge the skill?]
Ren stared at the system prompt in surprise. Attacking Gramps actually increases our friendship? It seemed the old man valued strength and progress above all else. If showing off his power made them "closer," Ren was more than happy to oblige. But he had one more card to play.
"Do you... practice the other forms as well?" Gramps asked after a long silence. If Ren had mastered the entire style through one epiphany, the world of demon slaying was about to be turned upside down.
Ren wiped the sweat from his brow, his mind spinning. "I feel like I've hit a ceiling with the Second and Fifth Forms," he lied smoothly. "The others... they're still a bit hazy. I haven't reached the bottleneck for them yet."
Gramps actually let out a visible sigh of relief. If Ren had mastered all six forms in one go, it would have been too terrifying to contemplate. Even a genius has limits.
"Rest for now," Gramps said, leaning on his cane as he turned toward the gate. "We will begin your true training this afternoon. I expect you to be ready."
The moment Gramps stepped out of the courtyard, his figure vanished. His prosthetic leg was no hindrance; he moved with the speed of a man half his age. Ren knew exactly where he was going, Zenitsu had likely made it halfway down the mountain by now and needed to be "retrieved."
Ren sat cross-legged in the center of the yard, taking advantage of the quiet to finish his transformation.
[Do you wish to fuse the skill: Thunder Breathing, Fifth Form: Heat Lightning?]
[Yes.]
The fusion of the Fifth Form was different from the previous ones. It didn't just focus on speed; it was about the raw, searing heat of the bolt. Ren felt his meridians toughen, becoming like reinforced pipes to handle the thermal output. When the process ended, the air in the courtyard returned to a deceptive calm.
Ren gripped his sword and pointed it at a distant rock.
"Fifth Form: Heat Lightning!"
A visible heatwave shimmered into existence around him. The grass beneath his feet withered and turned to ash in seconds. A sharp, scorched smell filled the air as the long sword turned a dull, glowing red.
With a low roar, Ren swung. A mass of golden electricity erupted from the tip of the blade. It wasn't a thin line like the First Form; it was a chaotic, expanding ball of lightning that devoured the air as it flew. It struck the rock with a deafening crack, leaving behind a jagged crater of molten glass and charred earth.
Ren nodded. The Fifth Form was his only long-range option, and its destructive power was terrifying.
Finally, he turned to the most important reward.
[Do you wish to fuse the skill: Total Concentration Breathing: Constant?]
[Yes.]
This fusion wasn't a burst of power, but a conceptual shift. It felt as if a new instinct was being woven into his DNA. Once the fusion was complete, Ren's lungs began to move on their own, drawing in deep, profound breaths that mimicked the rising and falling of the tide.
His mind guided his blood to flow faster, his heartbeat becoming a steady, powerful rhythm that never faltered. He felt his internal temperature rise, an invisible flame igniting in his core. This was the "Constant" state, the ability to maintain Total Concentration Breathing twenty-four hours a day, even while sleeping.
Ren didn't fight the feeling of being "incinerated" from the inside. He focused on the rhythm, allowing the power to grow without losing control. This was the hallmark of a true master, the foundation upon which the Hashira built their legend.
After a long time, Ren opened his eyes. The world looked different. He could feel the pulse of the mountain, the flow of the wind, and the terrifying strength coiling in his own muscles.
He was no longer just a spectator in this world. He was a predator. And the Final Selection was waiting.