Days blended into each other — a blur of aching limbs, shallow breaths, and the faint, rhythmic thrum of her heartbeat echoing through the cave.
Yuyan's body was changing. Slowly. Painfully.
Each morning she woke before dawn, rising from the cold stone floor with muscles screaming and sweat still damp on her skin. Her arms trembled whenever she pushed herself upright. Her legs wobbled as she tried to steady her stance.
And yet — she always rose.
Her training had become her world.
At first, she could barely finish half the routines written in the crimson book. The poses strained her balance, the breathing cycles left her dizzy, and the heat she summoned burned too wildly inside her veins. There were days she collapsed mid-stretch, panting, cursing under her breath.
"Whoever wrote this," she muttered once, glaring at the flickering crimson lines of the book, "had to be part demon."
The book, naturally, offered no sympathy — only more glowing script urging, "Continue until failure becomes silence."
She groaned, falling flat on her back. "I think failure's already knocking."
But she always got back up.
Every bruise, every drop of sweat, every time her body shook under its own weight — it all built something stronger beneath her skin. Her breath, once shallow and scattered, grew deep and steady. Her heartbeat no longer wavered with every burst of effort; it thudded like a forge hammer, firm and sure.
The air around her seemed to pulse in rhythm with her training. Each breath carried faint heat, the cave itself shimmering faintly as her body temperature rose. Her sweat hissed when it hit the stone floor, leaving faint scorch marks that cooled with a soft crackle.
When hunger clawed at her stomach, she foraged.
The cave mouth opened to a sparse forested slope. She found small fruits growing near the rocks — tart red berries and pale orange plums that left her lips sticky and sweet. They were not enough to fill her, but enough to keep her from fainting. She learned to time her meals between meditations, saving a few for nightfall.
Once, when her stomach growled mid-breath exercise, she pressed a hand to it and sighed.
"You and I both want fire, huh?"
The silence gave no answer. She laughed weakly to herself and continued.
Even the smallest of these moments — the little sounds, the fruit's tang, the ache of her limbs — reminded her she was still alive.
And that mattered.
Every evening, when exhaustion finally overtook her, she would rest her back against the cool stone and stare at the pendant on her chest. The faint crimson shimmer inside it pulsed gently, as if breathing with her.
On the seventh day, after finishing her last cycle of Iron Vein Forging, she felt it — the first true burn of stability.
Her fists trembled as she struck against the heated stones, her knuckles red and raw. But instead of pain, there was rhythm — flame surging through her arms, controlled, steady. Her breath flowed with her heartbeat, her blood like molten light moving through invisible channels.
When she stopped, steam curled from her skin. The cave glowed faintly, the heat lingering in the air like a soft hum.
She smiled weakly.
"Finally… that didn't almost kill me."
The book lay open beside her, pages faintly aglow. The next line pulsed as though waiting.
"When the veins no longer resist flame, seek understanding beyond flesh."
Yuyan frowned, leaning closer. "Understanding beyond flesh?"
Then she remembered.
The Crimson Library.
Her pulse quickened. She picked up the jade pendant that hung against her neck, pressing a small cut into her fingertip. A droplet of blood welled up, glowing faintly as it fell onto the pendant's surface.
The world shifted.
Crimson light flared around her, and the cave dissolved — replaced once again by the vast, endless library bathed in red.
The air was warmer this time, almost welcoming. The shelves pulsed faintly as if recognizing her. She stepped forward, her bare feet echoing softly on the polished floor.
Last time, she had come here in grief and confusion.
Now she came with purpose.
Her eyes moved along the titles until one caught her attention.
"Flame Forging for Mortal Bodies."
Her fingers brushed the cover. "That's more like it."
As she opened it, lines of molten gold rose into the air, swirling around her before pressing softly against her skin. Knowledge seeped into her — controlled breathing under heat, muscle hardening through rhythm, stabilizing heart and will.
One technique stood out among the rest:
Blazing Heartbeat Method (炽心法)
A breathing meditation that matches one's pulse to a flickering flame, forcing the body's rhythm to circulate in harmony with willpower.
It wasn't about absorbing Qi — not yet.
It was about creating endurance through control, shaping her inner rhythm into something that could one day sustain a cultivator's flame.
She could almost hear her mother's voice again, distant and kind.
"Your heart must lead your flame, not follow it."
Yuyan closed the book gently and bowed. "I'll remember."
Then she noticed another book beside it — thinner, its cover marked with faint claw-like patterns.
"Scarlet Pulse Circulation."
A body restoration method. It burned a single drop of blood essence to send warmth through the limbs, accelerating recovery and strengthening endurance. Dangerous, but powerful.
Her lips curved slightly. "So you train us to death, then teach us how not to die. Typical."
She gathered both books, cradling them against her arm.
When she turned to leave, the shelves behind her flickered once — not with fire, but with light, as though acknowledging her progress.
The crimson realm dissolved once more, fading into the cave's shadows. The air grew cool again, but inside, Yuyan felt a quiet warmth.
She placed the books carefully beside her bedroll — their glow faint, but steady. Then she sat, closing her eyes, beginning the Blazing Heartbeat practice.
At first, her pulse was uneven — too fast, too fierce. Her breath hitched as heat built behind her ribs. But she didn't stop. She slowed each exhale, counting heartbeats, until warmth and rhythm began to move as one.
Thump.
Breathe.
Thump.
Breathe.
The air rippled faintly. The cave's shadows danced, their edges glowing red as the heat within her deepened. Her blood surged through her body in steady waves — not Qi, but her own will, her life's flame spreading in slow, disciplined beats.
Her muscles tightened, veins glowing faintly beneath her skin. She felt the warmth trace through her arms, her legs, even her fingertips.
Outside, a faint gust passed through the forest, stirring the leaves near the cave entrance.
Inside, the girl at its heart sat unmoving, her hair lifting slightly in the warmth that surrounded her.
By the time she opened her eyes again, dawn had broken. Her limbs ached, but her breath was calm, her strength steady. Her hands — once trembling — now closed into firm fists.
Her reflection in the cave's spring showed faint lines of crimson pulsing under her skin, like threads of fire alive beneath porcelain.
Yuyan smiled faintly.
Her progress was small, but it was hers.
She bit into a small orange fruit she'd gathered earlier, savoring its sharp sweetness as she looked toward the rising sun.
"Flame Forging for Mortal Bodies," she murmured. "Fine. Let's see how far this mortal body can go."
The wind carried her words softly through the cave, mingling with the steady sound of her heartbeat — strong, bright, and unyielding.
The Xuèyàn flame burned on