Middle Eastern factions are united by one major similarity - they all have access to Semites for mercenaries - which consist of spearmen, archers, skirmishers and bow chariotry. Western factions such as Canaan and Egypt use the Egyptian tileset, while the rest - Babylon, Yamhad, Subartu and Elam use the West Asian tileset.
Anatolian
factions
Anatolian factions are named after their primary set of mercenary units - being Anatolian auxiliaries. Anatolian mercenaries sacrifice speed and armour for greater attack and hitpoints. These consist of the three Anatolian nations of the Lukka, the Kussarans and the Naharin.
While all three have access to Anatolian mercenaries, the Naharin have the benefit of being able to recruit Semites as well, just like their southern rivals Amurru and Subartu, and the Lukka have some naval prowess compared to their landlocked cousins to the east.
The wild Cimmerian peoples of Hammurabi consist primarily of three Aryan nations: the Iranians, the Indians and the Siberians. While they two share access to the Cimmerian recruitment pool, they have their own specialties - the Iranians share access to the Beidi with the Shang, while the Siberians too are capable of levying Rong people as do the Xirong, whereas the Indians represent the peoples of the Bactria-Margiana Archaeological Complex, en route to Bharat proper to the distant south.
West of the Lukka, within and across the Great Green lie the Aegean civilisations - being the Achaeans and the Minoans. These people, while similar in that they are seafaring nations like the Canaanites, Egyptians and Lukka, have a build style that is similar to that of the Anatolia factions, and are capable of recruiting Sea Peoples although it is to be mentioned that the Achaeans have a stronger heavy land force than the Minoans do, owing to their access to improved heavy spear infantry -- as well as the Balkan mercenary line.
European factions
While seemingly wild and uncultured, the peoples of Europe are born warriors by virtue of repeated patterns of migration, colonisation and resistance. The European list is dominated by the two Balkan nations of the Thracians and the Dardans, while 2 other faction -- the Euskaldunak, and the Europeans -- dwell to the far west and north. The Thracians and Dardans are capable of recruiting Balkan mercenaries, just like the Achaeans farther south, but other European tribes aren't so lucky.
By far the most diverse grouping of all, Asian factions are not so much a culturally singular group, but rather a series of four highly different and differing nations, each with their own playstyle and their own set of mercenaries which are seldom shared with one another.
Desert factions are named thus for the appearance of their buildings but here the similarities end. The Kushites are primarily a landlocked nation of archers, capable of raising African mercenaries like the ancient Egyptians, while the Maganites who have their strongholds strung out across the Musandam Peninsula themselves can raise Semitic mercenaries as well as that most quintessentially Arabian unit: camel-mounted warriors.