We're huge fans of Rome Total War Remastered at GameFront, so we have written our top 5 factions that you can truly feel satisfied after winning your campaign. Just a note we have not included any Roman factions in this as whilst it is satisfying to re-live history and conquer all and who doesn't like to have a well-disciplined army under them, we'll be going for the underdogs for that truly satisfying feeling.
5. The Seleucid Empire
The starting area of the Seleucids are vast, they control some of the wealthiest areas on the land but have the potential to control even wealthier ones if they can expand quickly into Egypt and also into modern-day Turkey. The units you start with are fairly basic, everyone is against you and wants to take your lands but if you play your cards right and weather out the storm you will have access to some of the best units when you upgrade your military buildings. You have Egypt to the south, Greece and Pontus to the West and North and Parthia to the East, a truly tough campaign but rewarding nonetheless should you get it right.
A very strong faction in their own right and you'll be wanting to take the Seleucids territories quite quickly or you'll buckle under the might of their late-game units. This faction however has very different units than what they actually had in reality. Their units will have mirrored that of the Greeks and Seleucids instead of what they have in the game which resembles more of a Middle Eastern dynamic. Your focus here will be on the Seleucids, to begin with, and possibly Parthia, but don't forget what lies to the west, a rich Carthage, domination of all Africa and of course Rome.
A difficult start financially and their infantry are pants which makes sieges and battles against the Seleucids pretty terrible. You will be relying on your cavalry and tactical genius to get around the phalanxes. The more west you push the more phalanxes you'll come up against with the factions of Greece, Macedon and Thrace. You'll need to capture those rich Seleucid lands quickly as well as the ones by the Nile so you can upgrade your financials to support your military upgrades. The most rewarding part of playing Parthia is upgrading your military to get Cataphracts, your heavy cavalry and saving grace when playing against the western powers, they destroy everything in their path.
They are built differently from Gaul and Britannia, they're slightly more disciplined with better-formed units consisting of almost hoplite units that can form a phalanx which really gives them the edge over the other barbarian factions they'll be fighting early on. The faction starts in a horrible financial situation so moving quickly on any rebel settlements and of course Gaul is a must. Gaul will be fighting the Romans in the south, Britains in the north and Spain in the west so take advantage and rip through. Being close to Rome has its dis-benefits, Rome gets involved in everything and the bully boy tactics they deploy will unhinge your campaign. This will happen mostly in the mid-game so Rome's units will be pretty tough to match against, hence why this is at number 2.
Okay, so I'm biased. My home faction and one I always love to play but in reality Britannia here are the true underdogs. Rome gets to her last unless Britannia starts to expand really quickly into Gaul as in some campaigns the AI does as Gaul struggles under the might of Rome in the south. Capture everything in Britain and that will set you right with a constant stream of money that you can use to fund your war effort south. The issue with playing this faction and the reason why it's so rewarding is that you face up against Rome after the Marian reforms (or just before) so their units are pretty heavily upgraded in their own right with more armour and experience from battles. After the Marian reforms, Rome get even bigger and better units. You'll also be facing up against the organised armies of Rome, Germania and even Carthage/Greece depending on if they have managed to deter Rome. The campaign begins quite easily but every turn you take will make it harder as the inevitable battle between your reckless hordes and the organised might of Rome will come to pass.