Chapter 4: Sun Breathing X First Use of Gyo
The smile felt both familiar and foreign to Roy.
In the Zoldyck household, he had never once seen Silva smile. It was as if the very concept of a smile was fundamentally incompatible with the face of a cold, unfeeling assassin. Not even a cruel smirk or a predatory grin. Nothing.
Sometimes, he wondered if Illumi's perpetually blank, doll-like expression was a direct result of their father's influence.
After all, the family elders had drilled one lesson into him more than any other:
"An assassin must never let emotion cloud their judgment."
"Joy, anger, sorrow, grief—all must be concealed. Only by achieving a state of absolute calm can one complete the mission without exposing oneself to unnecessary risk."
Perhaps it was because they saw that Roy could never truly achieve this state that Silva and Zeno had concluded his talent as an assassin was limited.
And they were right. More than an assassin, Roy was fiercely determined to be a person. The "job" came second. He refused to become a machine that had inverted its priorities, annihilating its own humanity for the sake of killing. That was the core reason he had always disliked Illumi.
Illumi was too... formulaic.
The family's "education" had systematically erased any joy he might have had as a child. He should have been like Nezuko, Takeo, and Shigeru, who were now swarming Roy, chattering excitedly, sharing their happiness, complaining about each other, and just being kids.
He shouldn't be spending every waking moment in monotonous training with the lifeless eyes of a dead fish.
A thousand thoughts flashed through Roy's mind in an instant. He was pulled from his reverie when the little guy, Shigeru, wrapped his arms around his leg.
The boy tilted his head back, his eyes wide and hopeful. "Big bro," he said in a piping voice. "Candy?"
Roy chuckled and pulled the small cloth pouch from his gi, tossing him a piece. That opened the floodgates.
Nezuko wanted one. Takeo wanted one. Roy was suddenly surrounded, his hands full. He patted Nezuko's head, gave Takeo a reassuring pat on the back, and reminded Shigeru not to eat too fast, all while trying not to get overwhelmed. The warm, chaotic scene, illuminated by the soft glow of an oil lamp, was reflected in Tanjiro's eyes. It was a sight that finally let him feel a sense of familiarity.
There he is. That was the big brother he knew. The phantom in the woods... that must have been a ghost that had possessed his soul.
"Big bro, I want one too!"
Tanjiro rubbed his face, a wide grin spreading across it as he joined the fray. Being the responsible one, he first helped Roy take the heavy basket of charcoal off his back, which was a huge relief.
Roy gave him a grateful nod. After satisfying the appetites of the little ones, he walked over to Tanjuro.
"For me?" Tanjuro looked at the single piece of candy in Roy's outstretched hand, a look of bewilderment on his face. When the realization sank in, a warmth spread through his chest and his eyes began to sting. He couldn't remember the last time he'd eaten candy. The memory was so distant, all he could recall was a vague image of his own father—Tanjiro's grandfather—when he was still alive.
He never imagined that his own son would now be old enough to bring him candy.
Tanjuro looked at Roy with gentle eyes and shook his head. "Fathers don't like sweets. You have it."
Roy didn't pull his hand back. "Father gets one," he insisted. "Grandmother gets one. Mother gets one. Everyone gets one."
Seeing his son's determination, Tanjuro knew it was pointless to argue. He smiled, unwrapped the candy, and placed it in his mouth, savoring the simple sweetness. As he did, he motioned for Roy to help him put on the ceremonial robes for the ritual dance.
The dance was a tradition passed down through the Kamado family for generations: an offering to the Fire God to pray for safety and protection from misfortune.
The ritual dance and the Hanafuda earrings that dangled from Tanjuro's ears—depicting a red sun over a mountain—were a secret that only Roy, a reader of the original story, understood. They were the legacy of Yoriichi Tsugikuni.
The Sun Breathing technique and the very earrings he wore in life.
"Since the time of our ancestor, Sumiyoshi," Tanjuro began as Roy helped tie the final sash, "our family has required the eldest son to learn the Hinokami Kagura. And now..."
"It is your turn, Eiichiro."
As the last rope was tied, the normally gentle Tanjuro stood up, and his entire presence changed. The red and white robes billowed in the wind, and the flame-emblazoned mask he wore seemed to come alive.
He beckoned to Roy. "Come."
Roy could barely contain his excitement. This was it. The opportunity to fundamentally change his physical constitution had arrived.
The Hinokami Kagura was Sun Breathing. It was the original and most powerful of all breathing styles, the wellspring from which all others—Moon, Stone, Wind, Water—had diverged. Created by Yoriichi through his observation of the sun, it was a technique that allowed a user to absorb the sun's power to radically transform their own body.
Of course, with great power came immense difficulty.
Long ago, Yoriichi had shared the technique freely with the Demon Slayer Corps, even teaching his own twin brother, who would later become the Upper Rank One demon, Kokushibo.
But none of them could master it. Neither Kokushibo nor the other swordsmen could withstand the sheer "weight" of the sun's power. From the Sengoku period to the present day, only Tanjiro had ever truly mastered it for combat, a testament to its incredible difficulty.
Roy grabbed Tanjiro's arm. "You too."
Before Tanjiro could process what was happening, Roy had already stepped into the courtyard, taking his place beside his father. He focused his mind and activated Gyo.
Narrator's Note: Distinct from the Four Major Principles of Nen (Ten, Zetsu, Ren, and Hatsu), Gyo is an advanced application. By focusing aura into the eyes, a Nen user can see things that are otherwise invisible, including another person's aura.
Thanks to Gotoh's meticulous theoretical instruction and the inherent talent of his Zoldyck bloodline, mastering this basic application was no trouble at all.
A milky-white layer of aura coated his eyes. He stared, unblinking, at Tanjuro's movements. By observing the flow of energy within his father's body, he could deconstruct the Hinokami Kagura, imprinting each movement into his mind like analyzing an animation frame by frame.
First, "Dance." Then, "Blue Heaven." Followed by "Raging Sun," "Burning Bones, Summer Sun," "Setting Sun Transformation," "Solar Heat Haze," "Thrusting Sun..."
Tanjuro became a spirit of fire, dancing gracefully amidst the heavy snowfall. Beside him, Roy followed, meticulously copying every step. And beside Roy, a clumsy Tanjiro stumbled along.
They went through the forms once, twice, three times.
Soon, Tanjiro was gasping for air, unable to keep up. He bent over, hands on his knees, panting heavily. His eyes were glued to his father and brother, his young mind filled with profound confusion.
Why was his normally frail father filled with such boundless energy?
And why was his brother, who had been just as clumsy as him moments ago, now able to match their father's movements so perfectly?