
The Sultanate is the form of goverment. It's like saying "The Republic" or "The Kingdom". What he meant by 'paladins of the Sultana' was "Sultansworn". That's their official name. They are not knights, though, in the sense that they have no lands or nobility title: they are just elite soldiers. Like roman Praetorian Guard, in a way.
It makes sense for them to be 'paladins', from a gameplay viewpoint, because gladiators hail from Ul'dah and I think their uniform is similar to the paladin artifact armor.
It makes sense for them to be 'paladins', from a gameplay viewpoint, because gladiators hail from Ul'dah and I think their uniform is similar to the paladin artifact armor.