Rel Borgen reigns as king on his home planet, Wedelun. He arrives on Earth with a mission to identify a protector capable of defending against extraterrestrial threats. Selecting Koujirou for this vital role, Rel provides him with a specialized transformation belt. This belt enables Koujirou to become the "Miracle Hero," granting enhanced physical and sensory capabilities.

Rel's primary focus is monitoring the belt's usage and ensuring Koujirou combats alien menaces threatening Earth. He frequently bristles with frustration and anger when Koujirou prioritizes impressing his romantic interest, Yuka, over his designated heroic duties. This establishes Rel as a figure of authority demanding strict adherence to his mission parameters.

His interactions extend beyond Koujirou to include Koujirou's horse, Hikarikin, who regards Rel with jealousy. Rel's role remains focused throughout the unfolding narrative, emphasizing his function as a catalyst for Koujirou's actions rather than undergoing significant personal change. He operates as a narrative device facilitating both comedic conflict—through his exasperation with Koujirou's distractions—and episodic superhero scenarios. His background as an alien monarch and unwavering commitment to the belt's intended purpose define his contributions.