Domingo Reubens is an experienced Trainer from the Cadrícean Sovereignty but with residence in Cuasto, an urban combat expert, and a member of the Elite Four of the Suocé region. He trains Zina Meness as part of his participation in Project Berilium.

Domingo had been part of a select group of Trainers trying to track down the activities of Black Thumb Gang since around 3723. In 3725, Ravir Eisenhorth took down Black Thumb's headquarters in Pradeimie and exposed their existence to the world, and Domingo Domingo was one of the elite trainers in charge of executing and finalizing the arrests and auditing the organization's HQ. To make sure Domingo's participation in the events remained hidden, the Conference Legislature gave underground support to the media's depiction of events showing Ravir as the main hero of the adventure.

Domingo went into obscurity for a few years after that, until he was recalled by President Gladys Farmalle in yr. 3728 when Virizion threatened a martial draft on the Sovereignty in the wake of the Fall of Pokefutures. Under presidential orders, Domingo infiltrated the police forces in Vys Ocassum and stole important data on the region's ace trainers that Pokefutures had been baking for recruitment plans, and then handed over those files to the League for examination. Unknown to both him and the President, the files were used to supplement a threat assessment brief resulting in the launch of Operation Registro Cero (Interim).

Some months after the events of the Fall, Domingo faced both Ravir Eisenhorth and Machalí sol Linaros as part of their E4 challenges.

While he never got official confirmation, Domingo believes his success in the exfiltration operation against Pokefutures is the reason why then President decided to not run for re-election. The resulting manhunt of Trainers and the lax involvement of then Champion Nadia Shepard in the subject matter were among the reasons Domingo and fellow E4 member Léos Ward came up with Project Berilium as a “subordinate E4”.

• “Stars of Suocé” (TBA) (debut)