The shadow beast loomed before them, its glowing red eyes piercing the dim light of the temple. It slithered forward, its form constantly shifting, as if it could never truly be solid. The air around it grew colder, and the once comforting glow of the Moonstone now felt distant, almost unreachable, as if the shadows were trying to swallow everything in their path.

Percy's breath quickened as the creature let out a low, rumbling growl. She could feel the pull of darkness, the weight of Nyx's power radiating from the beast. It was a creature born of pure night, its very presence a threat to the fragile peace that the Moonstone had upheld for centuries.

Beside her, Artemis was calm, her eyes narrowed in focus as she drew another arrow from her quiver, the silver shaft gleaming in the faint light. "This is it, Percy," Artemis said, her voice low but firm. "You need to combine your strength with the Moonstone. Only then can we stop it."

Percy nodded, her heart pounding in her chest. She could feel the moon's power inside her, calling to the crystal, but there was something else—something more primal. The ocean, the waves, the tides—they were all alive within her, thrumming with energy, waiting to be unleashed. But she had never faced anything like this before. Nyx's power was ancient, pure, and it seeped into every corner of the temple, weakening her resolve.

The shadow beast lunged forward, its claws slashing through the air. Percy didn't hesitate. She raised her hand, summoning the ocean's fury with a single thought. A tidal wave erupted from the ground beneath them, crashing toward the beast with the force of a hurricane. The water enveloped the creature, but it twisted through the liquid like a snake, its form not fully affected by the waves.

"Stay focused, Percy!" Artemis shouted, her voice urgent as she fired an arrow that pierced through the beast's shifting body. The arrow exploded on contact, releasing a burst of silver light that seemed to push the creature back, but it was quickly consumed by the darkness.

Percy could feel her strength waning as the creature pushed through the water. The shadow beast was relentless, and she wasn't sure how much longer she could hold it back. She glanced at Artemis, who was already notching another arrow, her expression one of determination.

"We need to seal the veil," Artemis said, her voice tight with urgency. "The Moonstone is the key. But you're the one who can empower it. You must connect with it, Percy."

Percy looked toward the Moonstone, its glow pulsating weakly in the center of the altar. It seemed to be calling to her, beckoning her to act. But the shadows of the creature were closing in, and Percy could feel the darkness creeping toward her.

"I'm ready," Percy said, her voice steady despite the rising panic in her chest. She stepped forward, forcing her legs to move even as the air grew colder with each passing second. The shadow beast was still charging, but she could feel the moon's energy grow stronger as she drew closer to the Moonstone.

As she approached the altar, the darkness seemed to recoil for a moment, as if the Moonstone's presence was a threat to it. Percy reached out, her fingers brushing the surface of the crystal. The moment her hand made contact, a surge of power shot through her, the ocean's depths crashing into her senses while the moon's light filled her soul.

It was overwhelming, but she didn't pull away. Instead, she allowed the power to fill her, allowing the moon and the sea to merge within her heart. She could feel the Moonstone's pulse, like a heartbeat, syncing with her own.

The shadow beast roared, charging forward one last time, but it was too late. Percy's connection to the Moonstone was complete, and the energy it released was unlike anything she had ever experienced. The water around her surged up, the ocean's tides rising with her command. The Moonstone flared brightly, casting a beam of silver light across the temple. The shadows recoiled, screeching as the light burned through the darkness.

Artemis shot another arrow, and this time, it struck true. The silver light seemed to merge with the Moonstone's pulse, and the beast screeched as the arrow found its mark, exploding in a shower of light and shadow. But even then, it wasn't enough. The creature was still alive, its form reassembling in the dark.

"I can't do this alone," Percy whispered, more to herself than to Artemis.

"You're not alone," Artemis said, stepping forward. "We're in this together."

Percy felt a warmth spread through her at Artemis's words, and for the first time since the battle had begun, she allowed herself to relax, if only slightly. Together, they were unstoppable.

With renewed determination, Percy focused on the Moonstone again. She called on the full power of the ocean, her hands glowing with silver-blue energy. The Moonstone pulsed again, its light growing stronger as she poured everything she had into it. Her connection to the sea, to the moon, and to Artemis—it all fused together in a powerful surge of magic.

The beast screamed in agony as the light from the Moonstone intensified. The ocean roared, crashing against the shadows, pushing them back. Percy's heart raced, her hands trembling, but she didn't falter. The power of both the moon and the sea surged through her veins, and with one final, deafening roar, the darkness was obliterated.

The shadow beast was gone, its form evaporating into mist as the last remnants of Nyx's influence were driven out by the light. The temple fell silent, the oppressive weight of the darkness lifting from the air.

Percy collapsed to her knees, breathing heavily, her body drained from the intense magic. Artemis was at her side in an instant, her silver eyes soft with concern as she knelt beside her.

"You did it," Artemis said, her voice filled with pride.

Percy nodded, her head spinning from the surge of power. "We did it."

For a moment, there was nothing but silence, the kind that only came after a battle was won. But in the distance, Percy could feel a new presence, one that was faint but growing stronger. It was Nyx—she could feel her essence lingering in the shadows, but for now, it had been held at bay.

"This isn't over," Artemis said, her voice quiet but resolute. "Nyx will return. We've only delayed her."

Percy stood up with Artemis's help, her legs unsteady but her resolve unshaken. "Then we'll be ready."

Together, they looked toward the horizon, knowing that this was only the beginning of the war against the goddess of night. And they would face it together.