The Demon king's Last oath

The sprawling estate of House Thorne was a world unto itself. Gardens stretched as far as the eye could see, the scent of blooming roses mingling with the fresh grass. Caius, now three years old, walked hand in hand with his nursemaid, Madam Lila, a plump woman with a kind smile and an endless supply of patience.

"Careful now, young master," Lila said as he toddled along, his steps steady but deliberate. "You're growing stronger every day. Soon you'll be running faster than the hounds!"

Caius remained silent, his small hand gripping hers. Inside his mind, however, his thoughts were sharp and calculating. At this age, he had no right to have such control over his balance, yet his body seemed to respond unnaturally well to his commands.

"It's faint… but the embers of my power are stirring."

His gaze shifted toward the far end of the garden, where his two older brothers were sparring with wooden swords. Lucian, now twelve, moved with precision and strength, while Julian, ten, stumbled as he tried to keep up.

"Stop dragging your feet, Julian!" Lucian barked, lowering his sword. "You'll never beat me like that!"

Julian panted, his curls sticking to his forehead. "Maybe I don't want to beat you. Maybe I just don't care about swords!"

Lucian scoffed. "Then you'll embarrass yourself in front of Father."

Caius's black hair ruffled in the breeze as he watched them. He could see it clearly—Lucian's growing pride and Julian's reluctance to conform. Neither boy had noticed him yet.

"Come now, little master," Lila said, tugging gently at his hand. "You've had your walk for the morning. Let's head back inside."

But Caius stopped, his piercing blue eyes locking onto the sparring match. "Wait," he said, his voice soft but firm.

Lila blinked. It wasn't often the young master spoke, but when he did, it carried a strange weight. "What is it, Master Caius?"

"I want to watch."

The boys noticed him now. Lucian frowned, while Julian smiled and waved. "Caius! Do you want to play?" Julian called.

Caius hesitated. He wasn't used to invitations like this. In his past life, no one dared "play" with him. He nodded, letting go of Lila's hand and walking toward them.

Lucian crossed his arms, eyeing Caius critically. "He's too young for swords."

"I can still learn," Caius said, meeting his brother's gaze with surprising confidence for a three-year-old.

Julian chuckled. "Look at him! He's already got that serious face. He's like a little general!"

Lucian rolled his eyes. "Fine. But don't cry if you get hurt."

Julian handed Caius a smaller wooden sword, its weight unfamiliar but not unwelcome in his hands. He gripped it tightly, his mind racing with muscle memory he didn't understand.

"Come on, then," Lucian said, raising his own blade. "Let's see if you can even swing it."

Caius took a step forward, his movements deliberate. He raised the wooden sword, mimicking Lucian's stance as if it were second nature.

Lucian's smirk faltered. "How does he…?"

Julian clapped his hands. "Look at him! He's copying you, Lucian!"

Caius didn't wait for further commentary. He lunged—not with the clumsy swing of a toddler, but with an unnatural precision that forced Lucian to raise his sword to block.

The sound of wood striking wood echoed across the garden. Lucian stumbled back, his eyes wide. "What—?"

Julian gaped. "Caius! How did you do that?!"

Caius didn't answer. He lowered his sword, his small chest rising and falling steadily. Inside, however, he was reeling.

"That movement… it wasn't just instinct. It was mine—a fragment of who I was."

Lucian's expression hardened, and he stepped forward again. "Beginner's luck. Let's see if you can do it twice."

But before they could clash again, a sharp voice rang out.

"Boys! What are you doing?"

They froze as the Marquess strode toward them, his imposing figure cutting through the sunlight. "Lucian, Julian, you were supposed to be sparring with each other, not dragging Caius into this."

"But, Father!" Lucian protested. "He wanted to try!"

The Marquess's gaze turned to Caius, who stared back unflinchingly. For a moment, the man's stern expression softened. "Is that true, Caius?"

"Yes, Father," Caius replied, his voice even.

The Marquess studied him, his dark eyes narrowing. "You're full of surprises, aren't you?" He sighed, rubbing his temples. "Lila, take Caius back inside. He's too young to be swinging swords."

"Of course, my lord," Lila said, hurrying forward to guide Caius away.

As she led him toward the estate, Julian called out, "You did great, Caius! We'll spar again soon!"

Lucian, however, said nothing, his gaze lingering on his youngest brother.

Later That Evening

Caius sat on the edge of his bed, staring at his hands. Moonlight streamed through the window, casting pale light over the room.

"That wasn't just chance," he thought, flexing his fingers. "I moved like I used to. My power… it's still there, buried deep. But why does it awaken now, in moments like this?"

A soft knock on the door interrupted his thoughts. It opened slightly, and Julian peeked in.

"Caius? Are you awake?"

"Yes," Caius replied.

Julian stepped inside, carrying a small plate of sweets. "I brought you these. You were so serious today, I thought you deserved a reward."

Caius blinked at the gesture, unfamiliar warmth spreading through him. "Thank you," he said quietly.

Julian grinned, sitting beside him. "You know, Lucian's mad because you almost beat him. Don't tell him I said this, but I think you might be better than him one day."

Caius looked at his brother, a strange ache filling his chest. "This bond… is this what humans call family?"

He took one of the sweets, biting into it slowly. It was strange and sweet, a taste he didn't recognize but didn't dislike.

For the first time in centuries, Caius smiled.