What factions are available in the game? How are extra factions unlocked?

You can play as the following factions in Total War: ROME REMASTERED’s three campaigns:

Base Game
Julii Brutii Scipii
Macedon Egypt The Seleucid Empire
Carthage Parthia Pontus
Gaul Germania Britannia
Armenia Dacia The Greek Cities
Numidia Scythia Spain
Barbarian Invasion
Western Roman Empire Eastern Roman Empire Huns
Goths Sarmatians Vandals
Franks Saxons Celts
Sassanids Roxolani Ostrogoths
Romano-British Slavs Burgundii
Berbers Alemanni Lombardi
Alexander the Great’s Macedon

To start only the three Roman factions are available in the Imperial Campaign – the Julii, Brutii and Scipii. When you defeat another faction, it is unlocked as playable in future campaigns.

After successful completion of an Imperial Campaign all factions will be unlocked.

To unlock all factions immediately, select Unlock All Base Game Factions from the Advanced tab of the Pre-Game Options window.