Isn't Vetinari A ?Vampire.
*I feel like im going to be beat with a stick for saying this.... it's the impression I got of Vetinari!
This was made ambiguous at times, rumor an suggestion but maybe I just haven't soaked up the whole Vetinari yet, I need to read some of the books again I think!
If he is a Vampire.... he will never have to leave us!
I did like how someone mentioned a republic/city state though. It does seem to me that the merchants guild, the thieves guild and all the other guilds have alot of political power at certain times. I think though that it is the Watch that is more likely, in several books I think the watch have overthrown a leader, in the history of A-M the same has happened and several times has Vetinari himself made some sort of deal or had a discussion with Vimes about the watch and its power.
Seems to me the watch would probably set up a transitional government, and never leave.
But to be fair, this is the thinking of a history student, I think Pratchett is far more creative than real life