William Parker was an aspiring engineer who used his skills to emulate the example of his idols in Superman and Batman of Earth-One while living in Metropolis' slums. Devising sonic powered equipment, he adopted the alter ego of Sonik, and worked alongside his two heroes aiding the World's Finest team in capturing a criminal gang. His prime motivation was to become a local role model for the youths in his community, and he would reappear on occasion to interact with the duo later on.
Charlie Bullock was an aspiring student who as a youth was mentored by Ted Grant, the Wildcat of Earth-Two, to learn how to defend himself in Gotham's slums. Obtaining a legal degree, Bullock still found himself faced by the criminal element when an armored assassin attacked the law firm he was employed at. Inspired by his childhood hero Batman and the current protector of that city in the Huntress, Charlie created a replica utility belt and assumed the alter ego of Blackwing to attack the Boa's gang. Blackwing had brief costumed career, when he found himself beaten by Boa, although Huntress' example inspired him to consider resuming his career later.