Nyet, not true...
Space Marshall is a rank equivalent to '5 star General' -- although it exists, it is hardly ever used. But although there is usually not even *one* SM, there can theoretically be a number of them.
The 'job' of a Space Marshall (as much as a rank can be assigned a task) is to command individual sectors and fleets... that leaves room for quite a number of them
Long live the Confederation,
Ben "Bandit" Lesnick
(email@example.com - 302228)