i dont know about the berbers, but the ERE annhilated the Sassanids, and the ERE later became the byzantines. They declined, but lasted up till 1476 when the Ottoman Turks took constantinple or whatever it is called. They almost survived until the rennisance.
Some Berbers got wiped out by the Visigothic Kingdom, those that survived existed alongside the ERE which anyway soon lost its African provinces. Same Visigothic Kingdom that sacked Rome once. It was destroyed by the ERE later on.
No not a mod, but a small isolated province right on top of Scythia which is defended by a faction called the Amazons. Or Amazonians. It's a town called Themiskyra, pretty tricky to conquer due to their chariots.