Vio is the ghostliest member of Team Rocket. As well as being a Ghost monotype trainer he is also a ghost himself, in the fact that his body is a puppet for the Bannette that lives inside of him.
Vio's journey began the second he died. On a family vacation to Dewford Town in Hoenn, Vio wandered off angstily and played with his precious Poocheyna. The Poocheyna smelled a strange scent coming from a nearby hill and went to investigate it, but as soon as he stepped up on the hill the ground collapsed beneath it and the dog fell into Granite Cave. Chasing after it, Vio tripped and fell into the pitch black cave without thinking and fell around 40 feet onto rocks, instantly killing him. Not much later, an inhabitant of Granite Cave found Vio and Poocheynas bodies and dragged them to a portion of the cave. This Sableye was the same one who Vio has today as his right-hand helper. The Sableye dragged Vio and his dog into the room of a particuarly skilled Bannette who reanimated Vio to strike a deal with him. The deal advantaged both parties, Vio would be able to stay alive (sort of) and essentially be immortal while the Bannette would get a free ride and cause mischief around the world with him. Vio accepted the deal, always desiring to be different and Vio signed his contract with the devil. The Bannette also freed the Poocheynas spirit into that of a Ghastly. From that day Vio and his ragtag band of undead wandered Hoenn, unable to be seen by normal human beings, as Vio had yet to control that aspect of his new power. After around a year of wandering and acquiring new friends (A Shedinja and a Duskull) Vio realized he didn't age, and would forever be a young adult. Eager to get on with his "life" Vio and his crew stowed away on the S.S. Anne which rode from Slateport City to Vermillion City in Kanto. He heard explosions from the North and naturally went to investigate where he wandered into Celadon where Tobi promptly swept him into Team Rocket's arms and pushed towards Alex as an obvious Special Operations candidate.