I decided to give my hand a try at figuring out where borders and cities would be. I used Europe as a base, but I think it's basically impossible to determine, however it was sort of fun to do.
I thought Tudor would be something like the Angevin Empire or a mix between it and Cnut's realm. It immediately comes into conflict with the German sounding names of the villains, however. I thought the idea of it as a thalassocratic empire was cool.
It boggled the mind where to put Grant. Originally I had it pegged as Scotland, then as Wales, and finally as the Danish island of Zealand.
Ys is just Ireland. Or Anglo-Ireland, or Anglo-Norman Ireland, or something. Also I moved Isle of Man to the West of Ireland. EDIT: Now that I think about it, wouldn't have made more sense for it to be Iceland? Since it's surrounded by ocean.
Midland is something like an English France or that's the impression I got out of its culture and attitude. I thought it might have been based on the Frankish empire, so I thought the kingdom would be very large, but I didn't know how much. It's supposed to encompass Normandy, Germany, Czechia, Slovakia, parts of Croatia and Slovenia (Frankish marches), and about half of Poland . I thought to include it, because on its territories was the homeland of the Eastern Germanics who are now extinct. My reasoning was that it would have been a central portion of Gaiseric's empire. I put Wyndham somewhere around Prague, but I have no idea where Doldrey, Koka, Enoch village, or where Godot's place might be.
Holy See territory is based on direct Papal States holdings from circa 1453 with some of Northern Italy as well. I chose that date, because that's when the Hundred Years war in Europe had ended. Albion based on the name and what's shown in ep. 135 I guess would have been in a mountainous area.
I had significant trouble with the Alliance of Paneria, which included Vritannis in its realm. At first I thought something like La Havre and its region in France, but then maybe it's Venice or Ragusa, or maybe the Hanseatic league. I settled with BENELUX countries. Even though they didn't exist in 1453...... I think Vritannis would be Rotterdam, then.
The Kushan empire is based on the First Persian empire.
The Duchies of Morgar and Wallatoria are somewhat based on Samuel's realm and Mircea the Elder's realm.
Because of its name, the Commonwealth of Randel is just Switzerland. I have no idea why I was so fixated on real-life equivalents.
Kingdom of Balden is whatever.