First step

After stepping into a room filled with the daunting presence of the demon's father, he solemnly addressed Deman, 'Deman, now at the age of sixteen... am I correct? There's something you must know about your mother. She was a beautiful slave, a woman whom I couldn't resist. And thus, you were born. But before her untimely demise, she gave birth to another child, a girl who is not mine, and I cannot bear responsibility for her. However, fate has entwined her as your sister, and it falls upon you to ensure her well-being.'"

Deman bowed respectfully, replying to his father, "I shall fulfill my duty, my lord."

Inside his mind, Deman mused, "I already knew about this... Is this why he brought me here?"

The king, observing Deman's prowess at dispelling his brother's magic, questioned, "Have you considered attending the magic academy of Sylvia? I perceive great potential within you to become a magic knight, capable of saving your sister through proper treatment."

"As you command, my lord," Deman dutifully responded.

The king, ending their conversation, proclaimed, "You may leave now."

Upon leaving the room, Deman made his way to the secretive confines behind the kitchen, where his sister and I resided. What he witnessed was both heart-wrenching and alarming – his sister was ensnared in a potent curse, a spell difficult for ordinary humans to undo.

"I believe I can break this curse," Deman muttered to himself with determination, gathering his magical energy.

With a surge of power, a dark aura enveloped the room, and a malicious spirit emerged from his sister's body, its words halted by Deman's decisive action. "Perish," he declared, and the spirit vanished into thin air. "You shall recover within a few days."

"Now I must confront these treacherous princes and the conniving queen," Deman resolved, his suspicions lingering toward the queen's involvement in their mother's untimely death, a puzzle he was determined to solve.