The door to the next Sanctum did not open so much as it breathed.
The stone dissolved into vapor, pulling inward like lungs taking in a long and deliberate inhale. Cold air rushed past Seraphina's cheeks, smelling of rain, ash, and something faintly metallic—like the tang of a blade drawn in silence. The others stiffened behind her, the Circle's steps echoing through the narrow passage carved deep beneath Empire High. Their torches flickered, then dimmed, as though even fire bowed before whatever waited inside.
Seraphina lifted the shard in her palm. It thrummed once—low, resonant, almost… mournful.
"Elijah," she whispered, glancing sideways.
"I know," he murmured back. His gaze stayed trained on the darkness ahead, sharp and alert. "The air's wrong."
Wrong wasn't the word. The air felt aware.
A thin mist slithered along the floor, curling around their boots like fingers tracing a threshold. Mei tightened the straps on her satchel, eyes narrowed as glowing chalk symbols shimmered around her fingertips. Riv twirled her twin blades, the metal vibrating lightly. Kaelina stood close to Tobias, visibly pale but resolute.
Tobias exhaled and muttered, "If this one tries to crawl into my childhood traumas again, I'm suing the Vault for emotional damage."
"It won't be the same," Seraphina said quietly. "Every Sanctum tests a different part of us."
"And this one?" Kaelina whispered.
Seraphina's fingers curled around the shard.
"It tests truth."
The mist recoiled as if it recognized the shard's pulse—and feared it. Elijah stepped forward first, his cloak brushing the dense air. For half a breath, nothing moved. Then the darkness opened beneath their feet.
Not a fall.
A pull.
A hand around the spine of reality itself.
Seraphina felt her body weightless, senses stripped away, sound ripped from her ears. The world inverted, twisted, and reformed—
—and suddenly, she stood in a vast, circular chamber filled with shimmering black water.
The Sanctum of Echoes.
The ceiling arched far above them, carved with spirals of glyphs that glowed faintly. The water did not ripple. It simply existed—flat, dark, silent. A perfect mirror that stretched across every inch of the ground except a narrow stone pathway leading toward the center.
Where an altar stood.
Where something whispered her name.
Elijah's hand grabbed her arm. "Don't step on the water."
"I know." Her voice shook despite her effort.
The others materialized behind them—flickering into place like figures coming into focus from another realm. Mei gasped softly, already reaching for her chalk, but the lines melted from her fingers when she tried to draw. Riv touched the water with her blade tip, and the steel screamed.
It didn't break. It shrieked.
"Okay," Tobias croaked, stumbling back. "Good! Great! The water is alive and hates metal. Perfectly normal things."
Kaelina tugged at his sleeve. "Don't joke."
"I'm not joking! That water just yelled at me!"
Seraphina stepped forward onto the path. The air thickened instantly, pressing against her skin like hundreds of invisible hands. She swallowed hard.
The Sanctum was watching.
"Stay on the path," she warned. "And don't look into the water too long."
"Why?" Riv asked.
Seraphina didn't answer. She stared at her reflection for only a second—and her blood froze.
It wasn't her.
It was her, but older. Stronger. Eyes glowing violet like burning twilight. Shadows curled from her fingertips, alive, hungry, obedient.
Power. Terrible power.
Elijah grabbed her chin and pulled her gaze away before she could breathe.
"Don't," he said sharply. "Not even a heartbeat."
Her pulse stuttered. "You saw?"
"No." His jaw tightened. "But I know what it does."
They walked.
Every step made the water shudder.
Every breath felt stolen.
When they reached the center, the altar pulsed—a block of obsidian with a single glowing sigil. It looked almost like a heart. Beating.
A whisper curled into Seraphina's ear—
Child of Shadow… come home.
She staggered. Elijah caught her elbow.
"Sera?" His voice softened, the edge of command slipping just for her. "Look at me. Stay with me."
She did.
And it grounded her.
Mei circled the altar slowly. "This Sanctum is older than the Academy itself," she said under her breath. "Older than the Vault. The glyphs… they're warning signs. This place doesn't create illusions. It pulls them."
"From where?" Tobias asked warily.
"The future," Mei whispered. "And the past."
A slow ripple passed through the water.
Then another.
Then—
Shapes rose.
Dark silhouettes. Humanoid. Featureless.
Echoes.
They stepped onto the stone path without disturbing the water.
"Form a circle!" Riv barked.
Blades hissed free. Mei summoned glyphs that sputtered but held. Tobias's palms burned with raw orange fire. Kaelina lifted her staff, breath shaking but her stance steadying.
Seraphina and Elijah stood at the front.
The Echoes halted.
Then split—
Each one shifting, reshaping, forming into versions of—
Them.
Sera felt her heart stop.
Her own Echo stood before her—eyes glowing that same impossible violet, hair swirling with shadow. Elijah's Echo stood opposite him—colder, darker, with shadows coiling around his wrists like chains. Tobias faced a version of himself with hollow eyes. Kaelina faced her mirror image curled around the illusion of her dead brother. Riv faced a version of herself drenched in blood. Mei faced herself wearing the robes of the first Vaultkeeper.
The chamber vibrated.
And the Echoes attacked.
The impact was instant.
Seraphina's Echo moved like smoke and lightning, shadows lashing like serpents. Elijah shoved Seraphina back just as a tendril snapped past his cheek, slicing open the stone wall behind him.
"Elijah!" she cried.
"I'm fine," he ground out, blocking another strike. "Focus on yours!"
Her Echo tilted its head—smiling with her face, her mouth, her eyes. "You know this is you," it whispered, voice echoing inside her skull. "The power you pretend you don't want."
"I'm nothing like you," Seraphina spat.
"Aren't you?"
It moved, shadow unraveling into chains that wrapped around Seraphina's wrists with impossible force. She fell to one knee as the Echo leaned in.
"You will become me. The Vault calls you. You feel it. Every time you breathe."
Elijah lunged, his blade cleaving through the shadow-chains. They burst into smoke. Seraphina dragged herself to her feet—
But her Echo didn't look at her anymore.
It looked at Elijah.
"And you… you're the tether that keeps her from embracing what she is."
"Shut up," Elijah snarled, stabbing at it.
The Echo caught the blade with two fingers.
And crushed it.
The steel cracked through the chamber like a scream.
Seraphina's breath punched out of her lungs. Elijah stepped back, shock flickering across his controlled expression for the first time.
The Echo smiled.
"She will outgrow you. Or you will break trying to keep up."
Seraphina's anger flared, molten and fierce. "You don't get to talk about him."
Shadows erupted from her hands before she realized she'd summoned them.
Her Echo blinked.
And grinned wider.
"Finally."
The blast hit, hurling the Echo backward across the chamber. The water rose in a violent torrent, shrieking.
Riv's Echo lunged at her with blood-soaked blades. Tobias fought himself and lost ground fast. Kaelina sobbed as her Echo dangled the illusion of her brother's hand in front of her like bait. Mei fought like a scholar possessed, her glyphs slamming into her Echo, which answered in identical strokes.
Elijah and Seraphina stood back-to-back, breathing hard, surrounded by shadows and flame.
"This isn't a fight we win individually," Elijah said between breaths. "It's reacting to us. Learning."
"Then we stop attacking separately," Seraphina said, chest heaving. "We combine."
Elijah froze.
"You mean—"
"Yes."
Silence.
Then—
He nodded once.
Shadows rose from her skin, curling around her arms. Elijah lifted his palms, light flaring—power drawn from the ancient discipline of Obsidian Knights, disciplined and razor-precise.
Her darkness.
His light.
Opposites.
Equal.
And devastating when united.
Their hands met.
The Sanctum groaned, the ceiling cracking. Water surged like something alive. The Echoes paused, their faces twisting in something that might have been fear.
"Now," Elijah whispered.
They unleashed everything.
Light speared through shadow. Shadow devoured and sharpened the light. The fused power roared through the chamber, ripping through the Echoes with unstoppable force. They dissolved, shattering into streams of smoke and light that swirled upward like fireflies caught in a storm.
One by one, the Echoes disintegrated.
The last one—Seraphina's—held her gaze as it faded, whispering—
"You will return."
Then nothing.
The chamber fell silent.
The water stilled.
The altar flared.
A new shard materialized on its surface—pale silver etched with runes shaped like tears.
Seraphina reached for it.
But Elijah grabbed her wrist.
"Sera," he said softly. "Wait."
His voice wasn't commanding. It wasn't rigid. It wasn't restrained.
It was… afraid.
She turned to him, heart pounding.
"Elijah?"
He searched her face as though trying to memorize her before something tore it away.
"What you did in there," he said quietly, "that power wasn't just instinct. It answered you. Like it knew you."
"It's mine," she whispered. "I felt it. It fits."
"That's what scares me."
She swallowed, throat tight. "Are you afraid of me?"
He stepped closer, shadows brushing over both of them.
"No," he said, voice breaking in the gentlest way. "I'm afraid of losing you."
Her breath stilled.
Something fragile and ferocious bloomed in her chest.
"Elijah…"
But before she could say anything more, the water stirred one last time.
A voice whispered through the chamber—not from an Echo, not from the Sanctum.
From the Vault itself.
"Three shards remain. And then… Seraphina Cole, you will awaken what sleeps in your blood."
The floor trembled.
The chamber shattered into smoke.
And the Sanctum threw them out.