The Southern Isles
(fanmade for fanfic, creative math with counting the rocks)
According to "A Frozen Heart", there are seven Isles. According to "Frozen Fever", a map looks like this, so I though - ok, it only counts as an isle if it is big enough/inhabitated/not connected by a bridge with another isle/whatever some of the kings said.
Also according to "A Frozen Heart", only the biggest Isle have any grass - the rest is rocky. Hence coloring.
As per a castle - the royal castle is, to be honest, only this part right next to the text. The rest, the part looking like a sea monster indeed, are defence walls. They can be, truly, very long. Only four, large windows are unusual, but hey, it's your castle. Also they are not exactly facing North, but close enough to be accurate.
The Brotherhood of the Isles is mysterious, I think it was meant to be some kind of religious order.
All the names are made up by me.













