The Demon king's Last oath

The nursery was a quiet place, sunlight streaming through the high arched windows. The soft cooing of an infant filled the air, accompanied by the distant chatter of nurses and maids.

Caius Thorne lay in a cradle of polished mahogany, staring at the spinning mobile above him. His tiny hands flailed toward the dangling silver moons and stars, his mind a storm of thoughts.

"This body… so weak. I can barely move."

The sensation was maddening. For centuries, he had commanded legions, his voice alone enough to cow even the mightiest warriors. Now, he couldn't even lift his own head.

A woman's face appeared above him—his mother, Lady Helena Thorne. Her blonde curls framed her face as she smiled down at him. "You've been so quiet, my little one," she murmured, her green eyes soft. "Almost as if you're lost in thought. Are you a scholar already, Caius?"

"Scholar? No, woman, I am—" His thoughts broke off as she tickled his cheek. A strange warmth bloomed in his chest.

"What is this… this feeling? Affection?"

The door creaked open, and the Marquess stepped in, his boots clicking against the marble floor. "Helena, how is he today?"

Lady Helena straightened, her smile widening. "He's perfect. He hardly ever cries, you know. Just watches the world with those deep blue eyes of his."

The Marquess chuckled, leaning down to place a hand on the cradle. "A quiet one, eh? Let's hope he stays that way. His brothers were terrors at this age."

At the mention of siblings, Caius stirred. He hadn't yet met the others—his older brothers who would surely tower over him in this pitiful form.

As if summoned by his thoughts, the door burst open, and two boys barreled in, each trying to push the other aside.

"Let me see him first!" cried the eldest, Lucian, his dark hair falling into his eyes as he shoved his younger brother aside.

"You always go first, Lucian!" retorted Julian, his golden curls bouncing as he fought back.

"Enough!" the Marquess barked, his tone commanding. The boys froze, muttering apologies.

Lady Helena sighed, scooping Caius into her arms. "Be gentle, boys. He's just a baby."

Lucian stepped forward, peering at Caius with narrowed eyes. "He doesn't look like much," he said bluntly. "Are you sure he's not just going to grow up boring?"

Caius glared at him—or he tried to. His infant muscles betrayed him, leaving him blinking instead.

Julian leaned in next, his face alight with curiosity. "He's looking at me! I think he likes me, Mother!"

Caius stared at the boy, studying him. Julian's cheerful demeanor was a stark contrast to Lucian's more calculating gaze.

"So, these are my brothers… They'll be useful. Or… obstacles."

The thought sent a pang of guilt through him. "No. I must not think that way anymore. This is a new life."

"Enough gawking," the Marquess said, clapping his hands. "Lucian, Julian, go to your lessons. Your tutors are waiting."

The boys groaned but obeyed, casting one last look at their baby brother before leaving.

Once the room was quiet again, Lady Helena sat in a rocking chair, cradling Caius against her chest. Her heartbeat thrummed softly in his ears.

"You're going to grow up to be strong, my little one," she whispered. "And kind. You'll make this family proud, I'm sure of it."

Caius closed his eyes, her words wrapping around him like a blanket.

"Strong, yes. But kind?" He clenched his tiny hands into fists. "I don't know if I can be that. Not with what I've done."