The Demon king's Last oath

The chamber crackled with tension as the figure stepped closer, their staff glowing faintly with dark energy. The beast at their side snarled, its massive claws scraping against the stone floor.

Caius tightened his grip on his dagger, the dark flames coiling around his hand flickering brighter. Beside him, the stranger shifted into a ready stance, their silver eyes locked on the figure.

"You don't know what you're dealing with, boy," the cloaked figure said, their voice low and resonant. "That shard belongs to my master. Hand it over, and I might let you leave with your life."

Caius met the figure's gaze, his blue eyes cold and steady. "Your master doesn't scare me."

The figure chuckled darkly, the sound echoing through the chamber. "Brave words for someone so young."

"Brave words for someone standing between us and that shard," the stranger quipped, their hands beginning to glow with faint silver light.

The figure's grip on the staff tightened, the energy around it flaring. "You've made your choice."

With a sharp motion, they slammed the staff into the ground. A pulse of dark magic surged outward, rattling the stone walls and extinguishing the faint blue light of the runes.

The beast lunged.

The creature moved with terrifying speed, its massive body covering the distance between them in an instant. Caius barely had time to react, raising his hand as the dark flames surged outward.

The fire struck the beast in the chest, sending it skidding back, but it barely slowed. It roared, shaking off the flames as if they were little more than an annoyance.

"Great," the stranger muttered, stepping forward. "Looks like we're doing this the hard way."

They raised their glowing hands, runes flaring to life along their arms. With a sharp motion, they hurled a burst of silver energy at the beast. The attack struck its shoulder, searing through its dark flesh and drawing a pained howl.

Caius moved quickly, darting to the side as the beast turned its attention to the stranger. His flames coiled around his dagger, the blade glowing with an unnatural heat. He charged, slashing at the creature's hind leg.

The beast roared again, its massive claws swiping toward him. Caius dodged, but the blow caught his shoulder, sending him tumbling to the ground.

"Focus, boy!" the stranger called, their silver energy forming into jagged, whip-like tendrils. They lashed out, striking the beast repeatedly and forcing it back.

Caius gritted his teeth, pushing himself to his feet. His shoulder burned, but he forced the pain aside, the flames around his hand burning brighter.

"Keep it distracted," he said, his voice steady.

The stranger glanced at him, a faint smirk crossing their face. "On it."

They stepped forward, their runes glowing brighter as they unleashed another barrage of energy. The beast snarled, its movements growing more erratic as it struggled against the onslaught.

Caius seized the opportunity. He charged again, his dagger slicing through the air as he drove it deep into the beast's side. The flames erupted, consuming the creature from within.

The beast let out a final, guttural roar before collapsing, its body dissolving into dark smoke that quickly faded into nothing.

The chamber fell silent for a brief moment, save for Caius's ragged breathing. But the reprieve was short-lived.

"You'll regret that," the cloaked figure said, their voice cold.

They raised their staff, the dark energy around it flaring brighter. Shadows began to gather around them, coalescing into humanoid shapes that moved with an unnatural fluidity.

Caius stepped forward, the flames around his hand flickering. "Your beast is gone. You're next."

The figure chuckled, their hood tilting slightly. "You're confident for someone who doesn't understand the power he wields."

"Try me," Caius said, his voice steady.

The shadowy figures surged forward, their movements quick and erratic. Caius met them head-on, his flames cutting through the darkness with ease. Each strike dissolved one of the shadowy forms, but more kept coming.

The stranger moved to his side, their silver energy forming into a glowing blade. They slashed through the shadows, their movements precise and efficient.

"You holding up, boy?" the stranger called, their voice light despite the chaos.

"I'm fine," Caius replied, his flames flaring brighter.

The cloaked figure watched from the edge of the chamber, their staff glowing ominously. "Impressive. But let's see how you handle this."

They slammed the staff into the ground again, and the runes along the walls flared with dark light. The air grew colder, and the ground beneath their feet began to crack.

From the center of the chamber, a massive shadowy form began to rise. It towered above them, its glowing eyes burning with malice.

The stranger cursed under their breath. "This just keeps getting better."

Caius clenched his jaw, his flames coiling around his entire arm. "Stay back. I'll handle it."

"Are you insane?" the stranger asked, but Caius was already moving.

The shadowy form lashed out, its massive arms sweeping through the chamber with terrifying force. Caius dodged, his small frame moving with unnatural precision. He raised his hand, unleashing a concentrated burst of flames that struck the creature's chest.

The attack burned through the shadow, but the form quickly reformed, its glowing eyes narrowing.

"You can't fight this alone," the stranger said, joining him.

Caius glanced at them, his blue eyes glowing faintly. "Then help me."

Together, they moved as one. The stranger's silver energy lashed out, striking the creature repeatedly and forcing it to focus on them. Caius used the distraction to close the distance, his flames flaring brighter as he struck again and again.

Finally, the creature began to falter, its massive form flickering as it struggled to maintain its shape.

"This is it," Caius said, his voice steady.

He raised his hand, the flames around it coiling into a concentrated sphere. With a sharp motion, he hurled it at the creature's chest. The flames struck true, consuming the shadowy form in a brilliant explosion of light.

When the light faded, the chamber was silent once more.

The cloaked figure was gone, leaving only the faint smell of ash and the lingering hum of magic.

Caius stood in the center of the chamber, his breathing heavy, his flames flickering weakly before fading completely.

The stranger approached, their silver eyes glinting in the dim light. "Well, that was fun. You still alive, boy?"

"Barely," Caius muttered, sheathing his dagger.

The stranger glanced at the shard on the pedestal. "So, what now?"

Caius looked at the shard, the pull in his chest stronger than ever. "Now, we figure out what this thing really is."