A-ou is an S-class ES member of the Galactic Organization of Trade and Tariffs (GOTT), assigned to the superpowered Shadow Unit enforcement division handling critical galactic missions. A-ou operates exclusively paired with partner Un-oh, adhering to the ES structure requiring agents of matching class rankings. Before joining GOTT, both A-ou and Un-oh honed their combat skills and tactical expertise as mercenaries. This past established a prolonged, intense professional rivalry with the C-class ES pair Éclair and Lumière; their interactions imply significant prior encounters shaping their dynamic within GOTT. Standard issue for each ES pair includes a customized advanced spaceship and a guard robot for mission deployment. ES abilities are categorized by power class, with S-class denoting high capability. While ES codenames often follow thematic or linguistic patterns, the specific origin of "A-ou" remains unelaborated. Within GOTT, A-ou and Un-oh are acknowledged by colleagues for their professionalism and combat effectiveness.