There are 3 races ingame, the Romans, the Egyptians, and the Barbarians (generally the various gaul tribes). Each has their own advantages and disadvantages, but also have very similar troops. There is 6 basic troop types, infantry, spearmen, swordsmen, archers, cavalry, and archer cavalry. In terms of infantry, theres the Auxiliary Infantry of the Romans, the Infantry of the Barbarians, and the Slaves of the Egyptians. Its a fairly weak troop, and is more of a builder
defences, siege units, and claiming villages. For spearmen, the basic Spearmen of the Romans, Pikemen of the Barbarians, and Guardsmen of the Egyptians. Nothing much to say about them, good against cavalry charges, good for holding a defensive life, weak in most other situations. For swordsmen, theres the Legionaries (they had to be in somewhere) of the Romans, the Warriors of the Barbarians, and Soldiers for the Egyptians. The main component of the army, good fighters, not the outright strongest troops (more later on that), but certainly the one you will normally have most of. Archer wise, Romans have the Auxiliary Archers, Bowmen for the Barbarians, and Archers for the Egyptians. They shoot arrows and are absolutely useless at hand to hand combat
what else is there to say? The cavalry are the Equites of the Romans, Noblemen of the Barbarians, and the Camel Riders for the Egyptians. Brilliant against archers and infantry, can hold their own against swordsmen, but will fall easily to spearmen. As you would expect really (like everything else so far I guess). Archer cavalry follow the same trend, the Romans have the Archer Cavalry, Barbarians have Mounted Bowmen, Egyptians have Camel Archers. Simply archers on a horse (or a camel), same strengths and weaknesses as normal archers, just a lot faster. In addition, all races have access to wolf scouts, hawk scouts, military leaders and healers, both of which take on different names for the different races. Through the campaign you experience many of the historical leaders, for example Agrado of Talagatta (Hawk scout), Caius Titus (Centurion/Military Leader), Cnaeus Gabinus (Centurion/Military Leader), Dubalix (Cheftain/Military Leader), Divitiacus (Druid/Healer), Titus Labienus (Centurion/Military Leader), Publius Licinius Crassus (Centurion/Military Leader), along with many more later on.
Also every race has 3 unique troops that only they can build, all of which are more powerful than their equivalent normal version. For the Romans, they have the Praetorian (hugely powerful, very difficult to kill, probably the best unit in the game), the Gladiators (slightly stronger than legionaries, but rarely fight entirely fair), and the Balearic Slingers (Archers who throw rocks instead of shoots arrows). The barbarians have the Hunters (very good at ambushes, otherwise just a strong archer replacement), the Berserkers (hugely powerful swordsmen type troop, rivals the Praetorians but wont survive drawn out battles), and a personal favourite of mine, the German Cavalry (Cavalry unit that can go into forests, and did I mention the ability to wipe out 1 regiment for no losses on occasion?). The Egyptians have the Nubian Archers (standard archers except they use poison tipped arrows, which wont heal naturally at all), Partian Cavalry (archer cavalry that can fire while moving, slightly stronger as well), and the war chariots (very powerful cavalry replacement, packs a huge punch per man
or horse
or whatever).
Finally I mentioned before that every race has its advantages and disadvantages:
The Romans have the strongest troops, best organisation, and just generally all round good. The Barbarians have the strongest troops man for man, however in most cases have regiments half the size of the Romans
balanced regiments, but equal men and troop type and leader competence, Barbarians win every time. The Egyptians have by far the weakest troops, however can recruit them so much quicker
100 vs 100 will lose, but 100 vs 500? Strength in numbers, but weak when you are prepared for them.
I think that is everything you could possibly need to know, and I dont expect you to need to know any of it really. How it all translates into mafia, I will give no hints, except that abilities/cover roles will make sense (i.e. I wont make slaves bulletproof).
