This first part of chapter 25 is somewhat hard to follow. Alma 25:5 mentions "the seed of Amulon" being "almost all slain" "by the hands of the Nephites." Then in verse 6 it says "the remainder" (of the seed of Amulon) "fled into the east wilderness," and "usurped power over the Lamanites." Where and how was the "seed of Amulon" "almost all slain?" And where was this first "east wilderness"? East of what? What is the reference point? And where was the second "east wilderness" mentioned in verse 8?
It might be that the phrase "east wilderness" does not mean, in these verses, a particular "East Wilderness", but rather just a location "east" of where the Amulonites were located. I feel that most all these battles in which the Lamanites were "driven" (Alma 25:3) and the Lamanites fled (Alma 25:8) have their beginning with the battle at the Sidon river in the "south wilderness." [Alan C. Miner, Personal Notes]
Geographical Theory Map: Alma 25:5-9 Amulonites Flee into the East Wilderness (11th Year)