Someone Explain The English Of "Vision of Empire"

When I googled vision of empire I found a bunch of books and just general usages of the term (albeit never formally defined) so I'd say it's just an idiomatic thing. The exclusion of the word "the" makes whatever they're talking about seem less definite and thus have greater potential, which is fitting for Swain when you consider that Noxus is supposed to be an expansionist nation.

Vision of the empire sounds too specific and definite. The ability refers to swains ambition and how he is still in the process of building this empire. His vision of it is fleeting at best, much like how the actual ability only provides a short glimpse of vision in the fog of war.