The years passed like a gentle river, washing away the cold cynicism of Hayato's former life. In the mountain estate of the Kurogane family, the silence he once feared was replaced by the rhythmic clack of wooden practice swords and the boisterous laughter of a clan that lived for each other.
To the outside world, the Kurogane were merely herbalists and charcoal burners, but within the walls of their compound, they practiced a craft hidden from the eyes of common men. They were practitioners of magic, an art that felt as natural to Hayato as breathing.
"Focus, Hayato! Magic is not about the strength of the blow, but the flow of your spirit," his father, Juro, called out. They stood in the central courtyard, surrounded by aunts, uncles, and cousins who watched with keen, supportive eyes.
Hayato breathed in, the cool mountain air filling his lungs. He felt the small, familiar weight of the Hanafuda earrings—a gift from his mother—clinking against his jaw. With a sharp exhale, he traced a sigil in the air with his finger. A faint, shimmering light followed his movement, wrapping around his wooden blade. Across from him, his cousin Ren smirked, echoing the gesture. They clashed, the magic reinforcing their wooden weapons so they rang like true steel. It was a friendly duel, one of hundreds, where the only prize was a warm meal and a pat on the back.
His education was a tapestry of family wisdom. His uncles taught him how to read the wind to predict an enemy's movement; his aunt showed him how to brew medicinal tonics; and his father drilled him in the precise use of their family's spells. To Hayato, this was simply the way of the world. He knew no other magic, only the sparks and shields he practiced with his kin.
But the most sacred moments happened at dawn.
Every year, as the first light of the new year touched the peaks, Hayato's mother, Shizuku, would perform the Hinokami Kagura. It was a dance ritual to the Fire God, a series of twelve segments performed from sunset to sunrise. Hayato would watch, mesmerized, as she moved with a fluidity that defied human limits, her breath hitching in a specific, rhythmic pattern. The Hanafuda earrings she wore—identical to his own—danced in the firelight.
"Why do you do it, Mother?" he had asked once, wrapped in a thick quilt as the snow fell.
"To keep the fire burning, Hayato," she had smiled, her face flushed from the exertion. "In our blood, and in the world. It is a prayer to the gods for protection and peace."
In those moments, surrounded by the scent of pine and the warmth of a dozen people who called him son, nephew, and brother, Hayato made a silent vow. He had been given a second chance at a life he never thought possible. He didn't want glory or complex secrets. He simply wanted this peace to stay forever. He wanted to grow old with these people, to protect the warmth he had finally found.
He did not know that the world of demons was closing in, or that the peace of the Kurogane mountain was about to be shattered forever.
******
The laughter that usually filled the Kurogane courtyard was gone, replaced by a suffocating silence. Hayato stood at the edge of the porch, his hand instinctively reaching for the Hanafuda earrings his mother had given him as he watched the scene before him.
His cousin, Ren—the same boy he had sparred with just days ago—was bound to a thick wooden pole in the center of the yard. His head hung low, and his breath came in ragged shivers. In front of him, resting on a stone pedestal, sat a book that seemed to swallow the morning light. It was an indestructible, cursed grimoire with a presence that felt heavier than the mountain itself.
"Father," Hayato whispered as Juro approached, his face like carved granite. "Why? Ren was just in the archives. Why is he being punished like a criminal for wanting to learn?"
Juro didn't look at his son. His eyes were fixed on the book. "He wasn't in the archives for a scroll or a map, Hayato. He was caught trying to break the seal on the Book of Void."
"But it's the Book of Void," Hayato argued, his confusion mounting. "It contains every magic theory ever written—the sum of all knowledge. If it's all in there, shouldn't we be studying it? To be stronger? To protect everyone better?"
Juro finally turned, and the sheer gravity in his gaze made Hayato flinch. "Strength is a trap, my son. Magic is a hungry, corruptive force. What we practice—the sparks, the mists, the gentle reinforcements—is Lesser Magic. It is safe because it is limited. But the Book of Void contains it all, including the Greater Magic."
He stepped closer, lowering his voice. "Those theories offer power that can level mountains, but that power is a poison. It twists the wielder's heart, dragging them toward the dark side until their humanity is consumed. It is a force of total corruption. In our family, only the elders are permitted to even look upon those pages, and only in the direst emergencies. To use it regularly is to invite a slow, inevitable decay of the soul."
Hayato was stunned, his mind racing through the history he had learned. "But what about the legends, Father? What about Abe no Seimei of the East, or Merlin of the West? They were the most powerful existences in history. Didn't they become legends because they mastered the Greater Magic?"
Juro shook his head slowly. "No, Hayato. You misunderstand their greatness. Seimei-sama and Merlin became legends not because they practiced Greater Magic, but because they used their resourcefulness combined with the efficient use of Lesser Magic. They reached the heights of power while remaining pure. They avoided the Greater path precisely because they knew it was a one-way trip into darkness."
Hayato looked at his hands, the same hands that called forth shimmering light during his duels. A chill settled in his bones. He realized that the magic he had been taught was a protective barrier—a way to defend himself without losing the person he had finally become. He was only "fine" because he had stayed within the bounds of the Lesser path.