Ulthark Marches

The Ulthark Marches, also sometimes called the Southern Marches or the Orcish Marches, are the boundaries separating human civilization in Orithea from orcdom in Ulthark. 
For long ages, these marches followed the southern frontiers of Vastemar and Sularia, where the mountainous highlands of those regions drop down precipitously to the sweeping savannahs of [Northern Ulthark plain]. That changed dramatically with the disastrous invasions of Gol Garga, which progressively swallowed up all of Vastemar and Sularia and pushed the new line of the Marches hundreds of miles north before they were finally halted at the decisive Battle of Crow’s Gorge. 
The new frontier between mankind and orcdom has uneasy stabilized along a line running through the Tigerstone Rift and the Druune Basin, and eastward across the Aghai Massif. The lands of Kelimaria, Ojaum, the Dranurian kingdoms, and the Sornele--once shielded behind the powerful martial states of Vastemar and Sularia--now find themselves on the front line of the new Ulthark Marches.