The Demon king's Last oath

The countryside surrounding the Thorne estate stretched endlessly—rolling hills, dense forests, and winding rivers that gleamed in the sunlight. It was the perfect place for three boys to roam, or so their father believed. The Marquess had sent Lucian, Julian, and Caius out under the watchful eyes of two estate guards to "enjoy the outdoors."

Caius, now five, trudged behind his brothers as they laughed and raced ahead. His black hair glinted in the sun, and though his steps seemed small and slow, he never lagged behind.

"Come on, Caius!" Julian called, his golden curls bouncing as he turned to wave. "You're like an old man back there!"

Caius sighed inwardly. "If only you knew." But instead of answering, he quickened his pace.

Lucian rolled his eyes, already climbing a rocky ledge. "Julian, stop waiting for him. If he can't keep up, that's his problem."

Julian frowned, crossing his arms. "He's your brother, Lucian. Stop being so mean to him."

Lucian shrugged, reaching the top of the ledge. "He's tough. He doesn't need you coddling him."

Caius climbed after them silently, his small hands gripping the rocks with ease. His brothers were so… loud. Yet their banter was oddly comforting. It was a far cry from the cold silence of his past life, where even his most loyal generals barely dared to speak in his presence.

"See?" Lucian said as Caius reached the top without hesitation. "Tough. Told you."

Caius dusted off his hands and glanced at the horizon. The forest ahead was dark and dense, the kind of place that whispered of danger and mystery. His instincts prickled—a faint, ancient sense that something lay hidden beyond those trees.

"Let's go in!" Julian said eagerly, pointing toward the forest.

Lucian hesitated, glancing at the guards who trailed them at a distance. "Father said we weren't supposed to go too far."

"Father isn't here," Julian countered, already heading for the tree line.

Lucian groaned, throwing up his hands. "You're impossible." He looked at Caius. "Are you coming too, or are you going to tattle like a baby?"

Caius's gaze lingered on the forest. Something about it pulled at him, a faint echo of power, distant but familiar. He nodded, following Julian without a word.

Lucian sighed. "Fine. But if you both get eaten by wolves, don't blame me."

The air changed the moment they stepped into the forest. The light dimmed, shadows stretching long and jagged across the forest floor. The chirping of birds grew faint, replaced by the rustle of unseen creatures.

Julian bounded ahead, oblivious to the eerie atmosphere. "Look at these trees! They're so tall!"

Lucian, less enthusiastic, kept close behind him. "Stay in sight, Julian. If you get lost, I'm not going after you."

Caius trailed behind, his senses sharp. The faint pull he'd felt earlier was stronger now, thrumming beneath his skin like a second heartbeat. His blue eyes scanned the trees, searching for the source of the disturbance.

"Over here!" Julian shouted, his voice echoing through the trees.

Lucian cursed under his breath. "Julian, stop running off!"

But Julian didn't answer.

A chill ran down Caius's spine. His small hands clenched into fists as he quickened his pace, following Lucian toward the sound of their brother's voice.

They found Julian standing in a clearing, his face pale as he stared at something on the ground.

"Julian?" Lucian said, stepping forward. "What's wrong?"

Caius followed, his gaze falling on the source of Julian's fear.

It was a wolf—or what was left of one. Its body was mangled, deep gashes running across its fur. But what struck Caius most was the aura surrounding it, a faint residue of magic. Dark, twisted, and unmistakable.

"Did something… eat it?" Julian whispered, his voice trembling.

Lucian grabbed his brother's arm, pulling him back. "We need to go. Now."

Caius's eyes narrowed. He knelt beside the carcass, his small fingers brushing against the cold fur. The magic was old, far older than anything a simple forest beast could wield.

"This isn't natural. Something—"

A low growl interrupted his thoughts.

The boys turned as a shadow emerged from the trees, its glowing red eyes locking onto them. It was a wolf, but unlike any they had seen before. Its body was wreathed in black mist, its jaws dripping with something unnatural.

Lucian stepped in front of his brothers, his hand reaching for the small dagger at his belt. "Run," he hissed.

Julian froze, his wide eyes fixed on the creature. Caius, however, remained calm. His heart pounded, not with fear, but with the rush of something long forgotten.

The wolf lunged.

Lucian shoved Julian out of the way, raising his dagger, but the beast was too fast. It barreled into him, knocking him to the ground.

"Lucian!" Julian screamed.

The wolf snarled, its teeth inches from Lucian's throat. But before it could strike, a wave of pressure rippled through the clearing.

The wolf yelped, its body flung backward as if struck by an invisible force. It hit the ground hard, whimpering as it scrambled to its feet.

Caius stood still, his small hand outstretched. His blue eyes glowed faintly, a flicker of crimson flashing within them.

The wolf growled, but it didn't attack again. It stared at Caius for a long moment before turning and disappearing into the trees.

Lucian sat up, his chest heaving. "What… what just happened?"

Julian rushed to his side, tears streaming down his face. "Are you okay?!"

Lucian nodded, though his gaze was fixed on Caius. "That thing… it stopped. It looked at Caius, and it just… stopped."

Caius lowered his hand, his expression unreadable. "It was afraid," he said simply.

Lucian stared at him. "Afraid? Of you?"

Julian turned to Caius, his face filled with awe. "Caius, that was amazing! How did you do that?"

Caius said nothing. His mind was racing. "The power… it's waking up."