Davie Wonder John, known as the hero Stardust, is the representative hero of England. In his civilian life, he is a world-famous rock star, a career that complements his public persona as a hero, as he is the only known hero whose true name and identity are a matter of public record. He is a tall man in his late twenties with spiky blond hair and tired-looking blue eyes, often hidden behind a pair of red sunglasses. His hero costume consists of a black bodysuit adorned with a gold five-pointed star on the chest, which he often covers with a beige coat.

Stardust is widely regarded by both other heroes and the public as an apathetic and almost heartless individual. He is straightforward to the point of bluntness, speaking of grim subjects with unnerving detachment, and is quick to judge others based on superficial observations. He initially views the Japanese hero Shy as incapable due to her naive nature and gentle heart. This reputation for being cold stems from his innate difficulty in expressing emotions and connecting with others, a trait that has followed him since childhood and once led him into fights when he was called heartless. Despite his claims of indifference, the accusations have affected him deeply.

His motivations are complex and rooted in a desire to do good despite his emotional limitations. He heeded the advice of a childhood friend who told him to become the nicest person on Earth, and he pursues this goal with a logic-driven commitment. Precisely because he does not form attachments easily, he is capable of making drastic, sometimes unethical, decisions for a greater cause. This includes performing brutal acts, such as tearing off a friend finger, to save him from a cursed object.

Stardust plays a significant role as a mentor and rival to the protagonist, Shy. He forces her into a brutal training fight to test her resolve and push her beyond her limits. His power, granted by his Heart-Shift Bracelets, is the ability to control all types of flows around him, allowing him to redirect physical attacks and other phenomena effortlessly. This power reflects his emotional state, acting as a barrier that prevents others from touching him. He is also a highly capable hand-to-hand combatant, easily overpowering Shy during their first encounter. His signature attack, Ashes to Stardust, consists of a series of powerful kicks that trace the shape of a five-pointed star.

Throughout the story, his rigid worldview is challenged by Shy, whose overwhelming empathy and determination force him to reconsider his own nature. When Shy claims that he has a heart, it stuns him, as only one other person had ever said that to him before. This interaction leaves a lasting impact, with Stardust later reflecting that he may also be capable of the naivety he once scorned. Beyond his hero work, he is a noted philanthropist, having donated billions to charity and founded the international rescue organization Black Cross. His most significant relationship is with the unnamed friend from his past, whose words and sacrifice continue to guide his actions.