The following is an overview of units from Age of Empires II and all its expansions.
The following units are available in any regular game. Not all of these units are available to all civilizations, unless the All Techs option is checked.
The most important building in the player's city. It serves as a drop off point for all resources, trains Villagers, researches some technologies, and can even fire arrows at enemies when Villagers are garrisoned inside. In The Conquerors expansion, the Teutons can research Crenellations, allowing their infantry to fire out of the town center as if they were Villagers. This can be trained at the Town Center:
One of the main military buildings, the Barracks, is a keystone of any effective army. Units trained there can be garrisoned inside for protection when the gather point is set on the building. No other units can be garrisoned inside and the units that can may only enter once. The Barracks trains foot infantry, researches some infantry improvements, and garrisons infantry. These units can be trained at the Barracks:
- Militia → Man-at-Arms → Long Swordsman → Two-Handed Swordsman → Champion
- Spearman → Pikeman → Halberdier*
- Eagle Scout ** → Eagle Warrior * → Elite Eagle Warrior *
- Huskarl (see note below)
- Condottiero (Italians Unique Unit, also their team bonus) **
The Goths can train Huskarls from the Barracks with the Anarchy upgrade. Any other civilization's Unique Units must be trained at the Castle (aside from the Longboat, the Turtle Ship, and the Missionary in " The Conquerors" expansion and also aside from the Slinger ,the Condottiero , the Imperial Camel and the Tarkan with Marauders technology in "The Forgotten" expansion).The Eagle Warriors can only be built by Aztecs, Incas and the Mayans, but when the mode is set to Full Tech Tree, then any player can build them. The Condottiero is a shared unique unit (team bonus) which means that if a player have an Italian ally, he or she can train them at their Barracks in the Imperial Age, for Italian players and their allies must have a Castle to have access to them. However, this requirement was removed in The African Kingdoms.
The first building that trains ranged units, the Archery Range is another necessity for competent players. It trains ranged attackers, which don't have to get into the thick of things to do damage, and excel at support for melee fighters. The following units can be trained at the Archery Range:
- Archer → Crossbowman → Arbalest
- Skirmisher → Elite Skirmisher → Imperial Skirmisher (Vietnamese Unique unit, also their team bonus) ****
- Cavalry Archer → Heavy Cavalry Archer
- Hand Cannoneer
- Slinger (Inca Unique unit) **
- Genitour (Berbers Unique unit, also their team bonus) ***→ Elite Genitour ***
Slingers requires a Castle before they are available. However, this requirement was removed in The African Kingdoms expansion. The Genitour is a shared unique unit (team bonus) which means that if a player have a Berber ally, he or she can train them at their archery range in the Castle Age, for Berber players to have access to them. It can be upgraded to the Elite Genitour in the Imperial Age. Similar to the Genitour, the Imperial Skirmisher is available as an upgrade to all civilizations who possess the Elite Skirmisher (all current civilisations with the exception of the Turks), if they have a Vietnamese ally.
The Stable trains mounted units, who excel at pursuing and charging. With the exception of Scout Cavalry, all of the units here have large amounts of health and attack, and all of them are quite fast. Just like in the real Middle Ages, a large enough force of Paladins is almost unstoppable. The following units can be trained at the Stable:
- Scout Cavalry → Light Cavalry → Hussar*
- Knight → Cavalier → Paladin
- Camel → Heavy Camel → Imperial Camel (Indian unique unit) **
- Battle Elephant → Elite Battle Elephant ****
- Tarkan (See note below)
The Huns in "The Forgotten" expansion have a new Unique technology. Marauders, that allows them to train Tarkans at the stable, just like the Huskarl with Anarchy. Imperial Camel is an upgrade to the Heavy Camel which is only available to Indians as they do not have any units from the Knight line.
The Siege Workshop can build Siege Engines, which have powerful long distance attacks. All of them have massive attack power, and most of them specialize in one thing, with the exception of the Mangonel. They generally work best against buildings, though there are exceptions. The following machines can be built at the Siege Workshop:
- Battering Ram → Capped Ram → Siege Ram
- Mangonel → Onager → Siege Onager
- Scorpion → Heavy Scorpion
- Bombard Cannon
- Siege Tower ***
The Monastery is the home of the Monk, who can do many useful things, such as healing and converting enemies; however, they have other abilities, too. For one, a Monastery can hold up to 3 Relics, which generate a steady source of gold, and work well with Markets. Additionally, the Monastery has plenty of good technologies to research. The following units can be trained at the Monastery:
Missionaries requires a Castle before they are available. However, this requirement was removed in The African Kingdoms expansion.
The Market is the building of diplomacy. Not only does it train Trade Carts, which can establish trade routes and bring in gold from other cities, but it can use trading to transform gold into other currencies, and even allows the player to pay tribute to friends and attempt to convert enemies. The following units can be trained at the Market:
Strong and sturdy, the Castle is the hallmark of a truly powerful player. They allow a player to train their civilization's Unique Unit, who will have powerful stats and unique abilities. Additionally, the powerful Trebuchet, although slow, can decimate enemies from uber-long distance, and the Petard can be sent in formations to immolate buildings in a split second. The Castle can fire arrows upon the heads of enemies, and the firepower only increases with units garrisoned inside. The following units can be trained at the Castle:
- Jaguar Warrior (Aztecs) *
- Camel Archer (Berbers) ***
- Longbowman (Britons)
- Arambai (Burmese) ****
- Cataphract (Byzantines)
- Woad Raider (Celts)
- Chu Ko Nu (Chinese)
- Shotel Warrior (Ethiopians) ***
- Throwing Axeman (Franks)
- Huskarl (Goths)
- Tarkan (Huns)
- Kamayuk (Incas) **
- Elephant Archer (Indians) **
- Genoese Crossbowman (Italians) **
- Samurai (Japanese)
- Ballista Elephant (Khmer) ****
- War Wagon (Koreans) *
- Magyar Huszar (Magyars) **
- Karambit Warrior (Malay) ****
- Plumed Archer (Maya) *
- Mangudai (Mongols)
- War Elephant (Persians)
- Organ Gun (Portuguese) ***
- Mameluke (Saracens)
- Conquistador (Spanish) *
- Boyar (Slavs) **
- Teutonic Knight (Teutons)
- Janissary (Turks)
- Rattan Archer (Vietnamese)
- Berserker (Vikings)
Note that each unique unit has their 'Elite' form, available at the Imperial Age only.
Even though it is one of the earliest available buildings, the Dock is quite useful. Given that most maps have at least one large ocean or river, the Fishing Ship and Trade Cog allow a player to bring in steady sources of resources, and the Transport Ship can cut across water to bring units where they need to be faster. Battleships built at the Docks are also powerful, as they can mostly fire upon landlocked units and structures without fear of retaliation. The following ships can be built at the Dock:
- Fishing Ship
- Trade Cog
- Transport Ship
- Galley → War Galley → Galleon
- Fire Galley *** → Fire Ship → Fast Fire Ship
- Demolition Raft *** → Demolition Ship → Heavy Demolition Ship
- Cannon Galleon → Elite Cannon Galleon
- Longboat → Elite Longboat (Vikings unique unit)
- Turtle Ship → Elite Turtle Ship (Koreans unique unit) *
- Caravel → Elite Caravel (Portuguese unique unit) ***
The Longboat and Turtle Ship initially required a Castle to be constructed before they were available, but this requirement was removed in The African Kingdoms.
Heroes and Kings are units which cannot be created in buildings. Heroes usually have high attack, defense, and health. They always have importance to the story of a scenario and the game is usually lost when these types of unit die. Kings appear in a game mode called Regicide, where the objective is to keep your king alive while killing the enemies' Kings.
(*) Units from "The Conquerors" expansion.
(**) Units from "The Forgotten" expansion.
(***) Units from "The African Kingdoms" expansion.
(****) Units from "Rise of the Rajas" expansion.