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[Enkidoh]

And another completely secret city beneath the Churning Mists called Sharlavan.

Uh, that is not another city state but is simply an error on the Eorzea map - that is Sharlayan, specifically, the Sharlayan colony that was abandoned which is located in the Dravanian Hinterlands (which you go to during HW's later story). Presumably the artist who made the map back during 1.0's original development didn't have very strong English-language skills, so it's just an example of Engrish rendered in Eorzean script.

So basically there are just six citystates in Eorzea - Gridania, Limsa Lominsa, Ul'dah, Ishgard, Ala Mhigo and the Sharlayan colony, and all are listed and accounted for on the map and in the game's lore.

[Ninimo_Babamo]

specifically, the Sharlayan colony that was abandoned which is located in the Dravanian Hinterlands (which you go to during HW's later story).

That is actually not the city state. It is just as you said, a small colony. The main city is believed to be on a tiny island northwest of Eorzea and still visible on the map though the writing is in the wrong place. That would be like saying Little Ala Mhigo is the city state of Ala Mhigo. They are separate places. And it is barely touched on at all in the entire 3.0 story.. Very hush hush.