Gouzou Aida is a salvager who founded the K2 Corporation after catastrophic global earthquakes submerged numerous cities. Transitioning from a previous career as an industrial spy, he established one of the first salvaging companies and set ethical standards for the profession. His commitment to principles, like refusing payment if his company damages salvaged goods, sometimes creates financial pressure and clashes with his daughter Rion, who views profitability as essential for survival.

During an earthquake that destroyed her parents' laboratory, Gouzou discovered and rescued Aika Sumeragi, who had been undergoing human enhancement experiments. He raised her, trained her in salvaging, and oversaw her attainment of a C-class salvager license. Despite her competence, he often treats her protectively, reflecting a paternal dynamic. This protectiveness extends to Rion, whose decision to become a salvager displeases him due to the dangers. He insists on the professional title "Chief" but prefers "Father" personally.

His leadership emphasizes practical efficiency and rule adherence, though he respects Aika's autonomy in accepting missions despite his risk concerns. He consistently prioritizes the safety of both Aika and Rion above business. Outside work, he enjoys karaoke and gambling, with occasional alcohol consumption sometimes triggering displays of unexpected combat proficiency, hinting at his covert espionage past.

Across multiple installments, he maintains his role as a mentor and father figure while managing K2 Corporation's operations and upholding his defined ethical code in salvaging.