Davie Wonder John is the hero representing Great Britain in the series, known publicly by his hero name, Stardust. He is a tall man in his late twenties with fair skin, spiky blond hair, and tired-looking blue eyes, often accentuated by dark circles under them that have been present since his childhood. In his civilian life, Davie is a world-famous and charismatic rock star, a career that has made him a celebrity as renowned for his music as for his heroic deeds. He is also a noted philanthropist, having donated billions to charity and founded the international rescue organization Black Cross.

Davie is widely perceived by both other heroes and the public as being apathetic and heartless. He speaks in a very direct, straightforward manner and does not shy away from discussing grim or violent topics, such as the time he was forced to sever a friend's finger to remove a cursed ring. He has a suspicious nature and initially judges others harshly based on superficial observations, once dismissing the Japanese hero Shy as incapable due to her gentle and naive demeanor. This apparent lack of emotion is not a choice but a lifelong condition; he has struggled with an innate difficulty in connecting with others emotionally since childhood. This led to fights and a reputation for being cold that has followed him into adulthood.

Despite his reputation, Stardust is a hero of immense capability. Because he does not get attached easily, he can make drastic, sometimes unethical, decisions for the greater good without hesitation. His career as a rock star was undertaken following a friend's advice to become the kindest person on Earth, using music as a medium to express feelings he could not otherwise convey. He truly cares about helping others, but he maintains a distance from them, something reflected in his hero costume which features a large, ostentatious star over where his heart would be. He was left stunned when Shy insisted that he does have a heart, as only one other person, an old friend, had ever told him that before.

Stardust's role in the story serves as a significant early challenge and foil for the protagonist, Shy. He is called upon to train her, and their fight becomes a brutal but pivotal moment for both characters. While he physically overpowers Shy with ease, he is unable to touch her spirit. Her overwhelming empathy and determination allow her to break through his defensive abilities, proving that her compassion is a form of strength. This encounter has a lasting impact on him, causing him to reconsider his own worldview and admit that he, too, might be capable of the "naivety" he once scorned. His key relationship is with Shy, whose refusal to be intimidated by him forces a crack in his emotional walls. He also has a deep, if mysterious, bond with a childhood friend whose advice shaped his entire life path.

Stardust's abilities come from his Heart-Shift Bracelets. His primary power is called Flow, which allows him to sense and manipulate all types of flows around him, including physical force, heat, and air currents. In combat, this effectively acts as a perfect defense, as he can redirect any attack thrown at him, making it nearly impossible for an opponent to land a hit. His offensive technique is named Ashes to Stardust, a powerful, high-speed kick that leaves a trail of stardust in the shape of a five-pointed star. His fighting style is brutally efficient, and he is a formidable hand-to-hand combatant who can easily defeat less experienced heroes without even appearing to move much.