The Demon king's Last oath

The estate library was one of the most expansive in the kingdom. Towering shelves stretched to the ceiling, filled with leather-bound tomes, scrolls, and maps from ages past. Dust motes floated lazily in the moonlight that streamed through tall windows, casting long shadows across the marble floors.

Caius slipped inside silently, his small frame allowing him to move unnoticed. The door creaked slightly as he shut it, but the silence of the estate reassured him. It was late, and everyone else should be asleep.

Except, he knew better than to assume he was truly alone.

"Lucian's been watching me closely since the forest," Caius thought, his blue eyes scanning the shelves. "And Father… he doesn't say much, but he knows something isn't right."

The thought made him uneasy, but he pushed it aside. Right now, he needed answers, and the library was the only place he could think to start.

He approached the oldest section, where the books were brittle with age and the words often faded. This was where his father kept records of the kingdom's history—wars, treaties, and legends.

Caius's fingers skimmed the spines of the books until they paused on a worn volume titled "On the Nature of Shadows."

He pulled it from the shelf, its weight surprising in his small hands. Sitting on the floor beneath the window, he opened it carefully, the yellowed pages crackling as they turned.

The History of the Shadowborn

The book spoke of creatures born of darkness, cursed beings who were neither human nor demon but something in between. They were often bound to powerful entities, serving as spies, assassins, or messengers.

Caius's jaw tightened as he read the description:

"The Shadowborn are marked by glowing red eyes and a twisted aura. Though weak on their own, they act as extensions of their master's will, capable of hunting prey over great distances."

The image accompanying the text was crude, but unmistakable—it was the same type of creature that had attacked him in the garden.

Caius's fingers tightened on the page. "So, it wasn't acting on its own. Someone sent it, just as I suspected."

He turned the page, his heart sinking as he read the next passage:

"The Shadowborn are bound to ancient magic, their existence tied to the remnants of the Demon King's reign. Even centuries after his death, they linger in the dark places of the world, searching for their master's essence."

Caius froze.

"Searching… for me."

He closed the book, his mind racing. It wasn't just his powers awakening. His very existence was drawing these creatures to him, and if the Shadowborn were finding him now, it was only a matter of time before something far worse arrived.

The soft creak of a floorboard snapped Caius from his thoughts. He spun around, the book still in his hands, and saw a shadow standing near the entrance to the library.

"Caius?"

It was Lucian.

Caius relaxed slightly, though his pulse still raced. He placed the book on the floor and stood. "What are you doing here?"

Lucian stepped closer, his dark hair ruffled from sleep. "I could ask you the same thing. It's the middle of the night."

"I couldn't sleep," Caius replied evenly.

Lucian's eyes flicked to the book on the floor, his brow furrowing. "You're reading… about Shadowborn?"

Caius didn't answer. He knew Lucian was smart enough to piece things together on his own, but he wouldn't make it easy for him.

Lucian crossed his arms, his gaze sharp. "What are you hiding?"

"I'm not hiding anything," Caius said calmly.

"You've been acting strange ever since the forest," Lucian pressed, stepping closer. "And then there's what happened with the wolf. Don't think I've forgotten. It was afraid of you, Caius. Why?"

Caius's hands tightened into fists at his sides. He wasn't ready to answer that question—not to Lucian, not to anyone. "You're imagining things."

Lucian scoffed. "Am I? You're just a kid, Caius, but sometimes you act like you're older than all of us. And then there's this…" He gestured to the book. "Why are you reading about Shadowborn in the middle of the night? What aren't you telling me?"

Caius met his brother's gaze, his blue eyes steady. "I'm protecting this family," he said quietly.

Lucian blinked, caught off guard by the statement. "Protecting us? From what?"

"From things you don't understand," Caius replied.

Lucian stared at him, his expression torn between frustration and confusion. Finally, he sighed, shaking his head. "You're hiding something. And I'll find out what it is."

With that, he turned and left, leaving Caius alone once more.

The next morning, the Marquess stood on the balcony overlooking the gardens, deep in thought. He had heard from the servants that Lucian had been seen leaving the library in the middle of the night, and while it wasn't unusual for his eldest to wander, it was Caius's name that had caught his attention.

The boy was becoming a mystery. Quiet, watchful, far more mature than any child his age should be. And then there was the incident in the forest. Lucian had downplayed it, but the Marquess knew his sons well. He could see when they were hiding something.

A knock at the door pulled him from his thoughts.

"Come in," he said.

Lady Helena entered, her expression bright as always. "You're up early."

"Couldn't sleep," the Marquess replied.

Helena joined him on the balcony, her gaze following his. "You're worried about the boys."

He nodded. "Mostly Caius."

Helena smiled. "He's a quiet one, but that's just his nature. He's always been thoughtful, even as a baby."

"That's what worries me," the Marquess said, his voice low. "There's something about him… something I can't explain."

Helena placed a hand on his arm. "You're overthinking again. He's just a child."

The Marquess didn't respond, his eyes still fixed on the garden where Caius sat reading under a tree.

As he sat beneath the tree, Caius flipped through another book he had taken from the library—a text on ancient seals and magic. His search had revealed little about how to stop the Shadowborn, but it had confirmed one thing: his power was growing, and so was the danger it attracted.

"If I don't control it soon, it will control me."

He glanced up at the estate, his sharp eyes catching the faint outline of his father watching from the balcony.

"And if they learn the truth… I'll lose this life."

He closed the book, his resolve hardening. "I need more answers. If the estate can't provide them, I'll have to look elsewhere."

As the wind rustled the leaves around him, Caius felt the faint pull of something in the distance—another fragment of his past, waiting to be uncovered.