Harry potter: I am the king of United Kingdom

The dim moonlight filtered through the dense canopy of the Forbidden Forest, casting eerie shadows that danced like specters on the forest floor. Arthur moved cautiously, his wandless magic at the ready, senses alert to every rustle and crackle of leaves. The message he had received—a mysterious note written in silver ink—had been unnervingly clear: "Come alone, or Pendragon blood will spill."

Arthur's pulse quickened as he pushed deeper into the forest. The chill in the air grew sharper, unnatural for the season. He could feel a magical presence, oppressive and cold, pressing against his skin. Then he saw them—cloaked figures emerging from the shadows, their faces obscured, wands drawn.

"You should have stayed in your castle, boy," sneered the tallest of the figures. His voice was like gravel, grating and cruel.

"I don't take orders from cowards who hide behind masks," Arthur replied, his voice steady despite the tension in the air. He raised his hand, summoning the wind around him, his grimoire glowing faintly at his side.

The figures didn't hesitate. Spells erupted from their wands, streaks of light cutting through the darkness. Arthur responded instinctively, weaving through the onslaught, deflecting curses with shields of air and retaliating with sharp bursts of wind magic.

Despite his skill, the ambush was overwhelming. For every assailant he struck down, two more seemed to take their place. His breaths came faster, his strength waning. Just as a well-aimed curse seared toward him, Arthur braced for impact—

A wall of ice erupted between him and the attackers, the curse shattering harmlessly against its crystalline surface. The air grew frigid, and a figure stepped out of the shadows, flanked by knights clad in enchanted armor.

The boy looked to be around Arthur's age, with piercing blue eyes and a commanding presence that belied his years. His hair, as white as freshly fallen snow, caught the faint moonlight. The cold radiating from him was palpable, his every step leaving frost in its wake.

"Who dares lay a hand on my brother?" the boy demanded, his voice calm but laced with menace.

Arthur stared, disbelief and confusion swirling in his mind. Brother?

The attackers hesitated, clearly unsettled by the newcomer. One of them snarled, "This isn't your fight, boy."

The boy smirked, raising a hand adorned with an ornate silver ring. The symbol of Merlin's insignia gleamed on its surface. "You made it mine the moment you threatened Pendragon blood."

With a flick of his hand, jagged shards of ice shot toward the attackers, forcing them to retreat. Arthur watched in awe as the boy manipulated the ice with precision, freezing their wands and binding their feet to the ground. The knights at his side moved swiftly, incapacitating the remaining assailants.

When the last of the attackers fell, the boy turned to Arthur, his expression softening. "You're lucky I came when I did. Father wouldn't want the Pendragon name tarnished by your untimely death."

Arthur's mind raced. "Who... who are you?"

The boy stepped closer, his breath visible in the cold air between them. "I am Atreus. Your brother."

Arthur staggered back, his heart pounding. "Brother? How is that possible?"

Atreus hesitated, his gaze briefly dropping to the ground. "We share the same father. My mother... she was the White Witch of Narnia. She died bringing me into this world." He looked back at Arthur, his blue eyes filled with a mixture of pride and sorrow. "I've been raised by knights loyal to the Pendragon name. They've prepared me for this moment."

Arthur's gaze fell to the ring on Atreus's hand. "That ring... is that Merlin's?"

Atreus nodded. "It's more than a ring. It's a key to our shared destiny. Together, we're meant to unlock the full potential of the Pendragon bloodline."

Before Arthur could respond, a groan from one of the attackers snapped them both back to reality. Atreus raised his hand, encasing the man in ice. "We need to leave before reinforcements arrive. There's much to discuss, brother."

Arthur nodded, still grappling with the revelation. As they left the forest, the weight of this newfound connection settled heavily on his shoulders. He couldn't deny the bond he felt with Atreus, nor the sense that their meeting was the beginning of something far greater.

In the distance, the lights of Hogwarts beckoned, a sanctuary from the chaos. But Arthur knew that his life—and his legacy—had just grown infinitely more complicated.