Peasants are reluctant warriors, but numbers are useful in all armies. Forcing peasants to fight is one way of getting lots of men in the field quickly and cheaply. They have little tactical sense, and even less willingness to fight - they would rather be defending their own homes rather than be dragged to a battle they neither care about nor understand. But if nothing else, they are useful when there's digging to be done! They are, however, experts at reading the land and hiding whenever there is cover.
Numidian javelinmen are fast moving skirmishers trained from infancy in the use of the javelin for hunting. They are recruited from amongst nomadic peoples who need their weapon skills to survive in harsh conditions.
They are best employed to harry enemies and thin their ranks with volleys of missiles. They should avoid being sucked into hand-to-hand combat, as their knives are more useful in skinning animals than killing men; also, other than a small shield they have no armour.
Historically, Numidian justice was extremely harsh on deserters and cowards: crucifixion was a common punishment.
(Note: they can be trained from the lowest-level barracks available to the Numidians, making them the equivalent of Town Watch in this sense.)
Slingers are highly skilled missile troops but are at a huge disadvantage in hand-to-hand combat, especially against cavalry. They can maintain a sustained and concentrated barrage on enemies and then fall back rapidly to avoid hand-to-hand combat. Slingers carry a shoulder bag with many pieces of lead shot (they can also use stones picked up on the battlefield) and several spare slings including slings of different length for greater or lesser range. Other than a knife and a small shield, they carry no other equipment.
These hardy folk from the fringes of the Sahara make excellent spearmen, well suited to defending against cavalry. They are tough troops used to eking out an existence in the unforgiving desert periphery. The prospect of a punishing march across great distances to these robust people is almost as familiar to them as the passing of each day. Equipped with spears and large shields of wood and animal hide, battle holds few fears for these people - life in a desert gives people a certain fatalism.
They are some of the best fighters available to Numidian commanders, but their lack of formal training is a slight weakness.
Numidian Legionaries are local copies of Roman Legionaries, but lack the truly awesome discipline of the originals. They have had training from Roman advisors, and this makes them the best trained of all Numidian soldiery. They cannot, however, use tactics like the tortoise (or testudo) when approaching enemy formations, but they do fight in the same fashion as the original Legionaries, first throwing heavy spears (pila) at the enemy and then closing for hand-to-hand combat.
A combination of rugged upbringing and harsh training makes them reliable and slow to tire in combat: a Numidian force can be sure that these men will do their duty.
Archers are rightly feared for the casualties they can inflict, but they are vulnerable in hand-to-hand combat.
They are drawn from the peasant classes of all societies, as these are the people who need to be skilled hunters in order to survive. Learning to use a bow well is something that takes a lifetime and constant practice, and putting food on the table provides good practice.
They are best used to weaken enemy formations, or placed in a spot where they can retreat and find protection from other troops.
Numidia produces some of the finest cavalry in all Africa, if not the Western Mediterranean world. Armed with javelins, these mounted skirmishers can be a nightmare for an opponent as it can prove practically impossible to pin them down in combat.
Their tactics are to pelt the enemy with deadly volleys of javelins, and then swiftly retreat when charged. If the enemy stand, they are slaughtered with volleys of javelins, and if they run the Numidian cavalry can ride them down!
Instinctive riders, the Numidians are famed for not using a saddle or reins, using only a stick to direct their horses. Nevertheless, they manoeuvre with the 'grace of a flock of birds'.
Having adapted to the broken expanses of their homelands, Numidian cavalry have great stamina, and they are also experts in their form of the Cantabrian circle attack.
These tough desert warriors are 'camel lancers', exploiting the speed of their mounts and the fear effect that camels cause to horses. The kings of Numidia are wise indeed to exploit this pool of skilled fighters. These are also a hardy people, and can put up with many privations thanks to their desert upbringing.
They are not the strongest cavalry in the world, but they can surprisingly effective against both infantry and especially other (horse) cavalry. Armed with spears and carrying large shields, they are not at their best in protracted melees, but used as hit-and-run raiders they can be very effective.
Long shield cavalry are spear-armed light cavalry, who can be used to break enemy formations, drive off skirmishers and pursue fleeing foes. This makes them a flexible and powerful force for any commander to have under his hand. They can also fight effectively in melee after a charge, as they carry swords of the falcata design. These are cunningly balanced so that the weight is towards the tip of the sword, giving a powerful cutting blow. Against spearmen, however, they can be at a disadvantage.
The onager is a catapult jokingly named for the tremendous kick it has when fired at the enemy (an "onager" is a wild ass). This war machine is powered by a twisted spring of animal sinew ropes, the most elastic substance available.
The throwing arm is held in tension by the sinews. When pulled back and held by a catch it can fling a boulder with considerable speed and range. This version can be used for reducing stone fortifications, but it can also be used on the battlefield for destroying enemy artillery and harassing troops (although admittedly by killing some of them outright).
The onager can also be used to launch incendiary missiles such as firepots, making it a versatile piece of artillery to any commander.
Strangely, the Numidians have the barbarian introduction upon starting their campaign. Initially, their territories are split in two, Cirta, Tingi, and Dimmidi in northwest Africa, and Siwa in northeast Africa.
Furthermore, should the player take Cyrene and have it revolt, it will become Macedonian. This will lead to a possible war with Macedon or the House of Brutii when they chase the Macedonians into Africa.
Numidia had two choices: attack Carthage or attack Egypt. In other words, Numidia can fight defensively in Siwa and offensively against Carthage, gaining control of Carthage's large population, size, rich trading routes, and (especially if Numidia decides to exterminate Carthage) large amount of loot; or fight offensively in the Nile region and fight defensively against (or ally with) Carthage. This allows Numidia to take the rich lands of the Nile Delta, but the player may inherit a war with the Seleucid Empire. In any case, the player needs to beware of invading Romans. However, since the Romans tend to be infantry-heavy, a good cavalry general can make short work of them. Should the player have sufficient money, they can try to bribe invading Roman armies (and the occasional band of bandits in their lands).
In either case, if Spain is not at war with Gaul or Carthage, they will likely attack Tingi. The best defense is a good offense, and seeing the Iberian Peninsula is fairly rich, Numidian players may wish to take Carthago Nova or Corduba (if they are at war with Carthage).
However, Numidia isn't a faction for everyone. It is challenging enough to fight on what is effectively three (isolated) fronts or even build a large army, but Numidia's economy will be the hardest thing to tackle, which is why taking Carthage/Egypt is so crucial. The desert lands are poor and lack resources, so trade won't exactly be very rich. Building farms is expensive and doesn't return much, and most of the cities have small populations and a small tax revenue. Combined with the necessary army-building this can bring an abrupt halt to the Numidian campaign even before the Romans or the Egyptians attack. Selling trade rights or map info or even alliances can help, but eventually the Numidian player will have to gain money through conquest.
All said, Numidia can be an entertaining faction to play as, but it is also very challenging and failures will be frequent to the inexperienced player.
In the Custom Battle, an addition has been made to Numidia's army: mercenary war elephants (assuming the game files are unedited). This improves their army a lot and greatly increases their overall effectiveness. Also Numidian generals can afford to play a bit more recklessly since they don't have to worry as much as taking severe losses.
Numidian Cavalry are very useful, as they can be used to rear-charge, bait, and harass enemy infantry and outrun most heavy cavalry. Horse archers are a big problem though, so Parthia and Scythia will be very challenging for Numidia to defeat. Cavalry in general will be essential for Numidian victory.
In general, Numidia in the Custom Battle relies on their cavalry more than, say, the Romans or Greeks do. Having elephants is extremely and may be the best way to defeat enemy phalanxes. If other mercenaries are available, they will help greatly.
In campaign battles, the scale tend to be smaller as Numidia can't host as large armies often and nor can their enemy. Their general's bodyguards also plays a bigger role, as they are their most effective heavy cavalry. Before a battle, Numidian generals should try to bolster their ranks with mercenaries.
Numidian Cavalry should form the cornerstone of early Numidian armies, due to their inferior infantry (their militia-level unit are peltasts). Fast and agile, they're worth keeping into later game. Long Shield Cavalry is useful (more than Numidian Legionaries) against infantry, and Numidian Camel Riders are effective against cavalry.
Siege warfare is more uniform compared to field battle for the factions. However, Numidia's weak infantry can let them down somewhat in street fighting, and since cavalry is needed to effectively rout enemy formations, Numidian players should either breach the walls in multiple places or spread their cavalry out so that they aren't forced to fight in one place.
Often it's better to wait for the enemy to sally out and attack, because of Numidia's reliance on cavalry and its inferior infantry.
In defending roles, Numidia performs slightly better, due to bottlenecks and chokepoints formed by the city's walls and streets. A sallying Numidian force, if not defeated as they come out of the walls, can transform the sally into a regular field battle.