Vivoide's direct translation means warlord, but it is generally a term for a steward or a viceroy or governor, although its most famous usage, for Wallachia, was the ruler there outright. 

It was meant to be that there was a Visha governor who oversaw Vos before the collapse of the empire, hence why they don't have a single head of state now, because their head of state was always Visha.