Fire Emblem: The Age of Legend
Encompassing all the land within the Taraka, Frysolythian, and Kitatani Mountains as well the Peruvian Hills and usually considered to include the remaining lands along the delta of the River Kora, this vast region is among the most fertile and populous in all Feryngia. Sloping gradually up from the vast Lake Kora out in all directions to various mountain ranges it catches a vast amount of rain and is thus streaked all over with tributaries flowing into the eponymous lake or river.
It corresponds now to the countries of Savaritania, the Koran Free Cities, and a bit of the Frysolythian Empire. Conquering it has been a major objective of several states over time though due to its vast wealth. Notably both the Savlan Empire and Frysolythian Empire were able to occupy all of it at least occasionally and most of it for a very long time.
Even the frequent fierce and bloody wars like the vast conflict called the Greater War of the Dragons cannot depopulate or impoverish it for long.