He and his brothers have an incredibly loud monotone voice, a jab at the voice 4Kids used to dub him, and also because they are wearing headsets. His brothers were discovered cheating by Mokuba.
Rex Raptor compares him to Charlie Brown, likely due to the zig-zag stripe pattern on his shirt. His rare card, Jinzo, destroys Internet references. Despite Joey's deck being mostly made up of Internet references, he still manages to win. He appears again in the "What Would Yugi Do" special, featuring him and his family trying to give away or trade their baby it to Yugi for Buster Blader. When he refuses to trade it, Roba replies that it doesn't deserve a slot in his deck, but that he could use it as a coaster. This is a reference to the original 4Kids dialogue, where he says the same after defeating Rex. This quickly becomes a catchpharse for Espa Roba, who even claims that he could use the Baby Jesus as such.
It's also revealed Roba is 37 years old, that he and his brothers are a family of carni's, and that the reason they want to give away the baby is because it doesn't deserve to be a trapeze artist. In "Desperately Dueling Susan", it is revealed that Espa and his brothers sold their baby to Joey after their duel. The baby had proved a nuisance to Serenity (and later on, Ishizu) however Joey considers it to be money well spent. The baby is later killed offscreen by Melvin.
He is also seen having a prediction war with Ishizu in the Third Anniversary video.