Age of Empires 2 is a complex game where each military unit has a role to play in battle; each military unit is a counter for another unit and may be countered by another unit. See the counter guide below to understand what the strengths and weaknesses of each unit is.
The militia-line are an infantry unit. This includes militia, man at arms, long swordsmen, two-handed swordsman and champions.
Militia can be countered by the archer-line, knight-line, hand-cannoneers and massed scorpions.
Militia counter trash units (skirmishers, spearmen, scouts) and eagle warriors.
The archer-line is a ranged, high damage-per-second, low health unit. The archer-line includes Archers, Crossbow and Arbalest
Archers can be countered by skirmishers, siege or eagle warriors.
One particularly effective method of dealing with archers or crossbow is by using a few rams patrolled in front to soak up damage, while other units attack. Archers that are on patrol naturally attack the closest unit until that unit is killed, and then attack the next closest unit, meaning that archers require lots of micro to win-out against this strategy.
The archer-line is effective against infantry and even cavalry when they reach a critical-mass.
The knight-line is a cavalry unit. The knight-line includes knights, cavaliers and paladins.
It can be countered by spearmen (although they beat spearmen one on one), monks and archers when those archers have a critical mass, and typically when they are crossbowmen. Due to how expensive knights are, resulting in a difficulty or delay in massing them, monks are the ideal counter.
Knights are a is a high hp, high armor and high attack unit, and are relatively easy to use. Knights are very effective against skirmishers, siege, infantry (other than spearmen) and hand cannoneers. Knights also are an effective unit to raid an opponents economy, as they usually can stand up to town-center fire where other units struggle, and have high mobility.
The spearman-line is an infantry trash unit. The spearman-line includes spearman, pikeman and halberdiers.
Spearman can be countered by archers, skirmishers, militia, scorpions or hand cannoneers. Generally speaking, anything that is not cavalry will counter the spearman, however mangonels may struggle if the spearman closes the distance and gets into the minimum range.
Spearman are an anti-cavalry unit. While scouts with bloodlines are the strongest units in feudal aggression, spearman on scouts will deal the highest damage that any unit can deal on another in the feudal age. Spearman are relatively cheap to produce and to upgrade and is essential in most games that go into the late game.
As with all the the three trash units, spearman are countered by one trash unit (the skirmisher) and counters one trash unit (the scouts).
The skirmisher is an archer class trash unit.
Skirmishers are countered effectively by the knight-line, scout-line, eagle warriors, siege and militia-line. This is as, although they have high pierce armor, they lack melee armor, are low hp and have a minimum range, rendering them unable to attack melee units.
Skirmishers are an anti-archer unit however, they have significant bonus damage to archers and have additional pierce armor which assists in defending from them.
Like all trash units, skirmishers excel against one trash unit (the spearmen-line) but are weak against another (the scout-line).
The scout-line are cavalry trash units. The scout-line includes scouts, light cavalry and hussars.
Scouts can be countered by spearman or militia, knights, or massed archers.
Scouts are very effective against monks as they have a conversion-resistance and deal bonus damage to monks. Scouts are also effective against skirmishers and is an ideal cheap raiding unit to damage an opponents economy due to its mobility. Since it is a trash unit with high hp and pierce armor, scouts are often used as what is called a “meat-shield” to assist with ranged units dealing damage but not taking damage, ensuring the ranged units behind can have a net-positive production increasing the changes of an effective snowball.
As with all trash units, scouts are effective against one form of trash unit (skirmishers) but struggle against another (the spearman).
Monks are an interesting unit, however they require a lot of micro, due to the fact that they are unable to be patrolled for conversions. For this reason, skirmishers, archers, and spearman are effective against monks, as they are a unit which has low hp (reducing the risk of a single conversion) and are required to be massed to be effective. Scouts are particularly effective against monks due to additional bonus damage that monks take from them, and also due to the fact that scouts benefit from a conversion resistance.
Monks can change the tide of a battle. In particular, they are effective against the knights and especially effective against any form of elephants, due to low mobility of the elephants, high hp and attack of each elephant increasing the worth of a conversion, and the fact that they are so expensive that massing these elephants are difficult.
Where a civilization also receives redemption, monks are also highly effective against mangonels, scorpions and bombard cannons, which can be converted from the distance. This is due to the fact that siege is very expensive to mass, and therefore the value of the conversion is increased.
The eagle-line are a fast-moving infantry unit only available to the meso-american civilizations. The eagle-line includes eagle scouts, eagle warriors and elite eagle warriors.
In the early ages of the game eagle scouts are similar to the scouts, however it becomes its own unit with the eagle warrior upgrade. Eagle warriors excel in raiding and fighting archer units. Eagle warriors also have some conversion-resistance.
Eagle warriors can be countered with militia, hand-cannons, siege, slingers, and knights can take cost effective trades against them.
Eagle warriors counter archers, monks and are excellent at raiding economies.
Camels, also known as camel riders since the release of Definitive Edition, is a cavalry unit that is used for anti-cavalry purposes.
Camels can be countered with the spearman-line, monks, or the archer-line. Camels also take more damage from defensive buildings than other cavalry units.
Camels excel against cavalry such as the knight-line and scout-line. Camels can also be used against skirmishers and for raiding, although other units may be more cost effective for raiding.
The Cavalry Archer is a high mobility, high damage-per-second unit useful for raiding or when massed.
Cavalry archers can be countered by skirmishers, siege and eagle warriors. Monks can also counter cavalry archers if they are not yet massed, as monks have plenty of additional range. Spearman also have bonus attack against them, however they are not the best unit to counter cavalry archers due to their low pierce armor, hit-and-run micro and due to the extra attack parthian tactics give cavalry archers against the spearman.
Cavalry archers excel against most infantry due to their pierce damage and hit-and-run capabilities. They can also counter cavalry when they reach a critical mass. Cavalry archers are one of the best units in the game for raiding an opponent, especially in the opponents trade line.