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Ranged siege weapon with area of effect attack, but cannot attack enemies at close range. Strong vs. tight groups of units. Can attack ground and destroy trees.
Age of Empires II description

The Siege Onager is a ranged siege unit in Age of Empires II that can be trained at the Siege Workshop once the Imperial Age is reached. It is primarily used against large groups of enemies. Its high attack and splash damage make it a powerful unit, especially against dense groups of archers and slow-moving units. As a ranged unit with blast attack, it also causes friendly fire. Its main offsets are its low movement and projectile speed, minimum range, high cost, and tendency to harm friendly units caught in its blast.

Availability chart[]

Siegeonageravailable AvailableSiegeonagerunavailable Unavailable
- means that the civilizations does not get Siege Engineers. Consequently, it cannot fully upgrade its Siege Onager.
+ means that the civilization gets some civilization or team bonus or a unique technology that benefits the combat strength of the Siege Onager.


Siege Onagers are arguably the most powerful siege weapon when it comes to killing other units. They are devastating against archers and slow-moving units, they excel at crushing other siege weapons, but cannot defend themselves against most melee units. Therefore, they need to be guarded in most situations. Siege Onagers are often paired with Halberdiers, as they can be a buffer for melee units and deal significant damage to cavalry. That combination is especially prominent with the Bulgarians, Celts, Ethiopians, Koreans, Teutons, and Slavs, as all have either a civilization bonus or unique technology that benefits the strength of both. Archers can also be used, because the player's own melee units are usually endangered by the Siege Onagers, but archers do not adequately cover cavalry, the Siege Onager's main weakness.

The Siege Onager upgrade comes with +10 hit points, +25 attack, +15 anti-building attack, and +0.25 blast radius. As Siege Onager is one of the most expensive upgrades in the game (but also one of the most powerful), the player has to carefully weigh whether it is worth it in a 1v1 game, but it can definitely turn the tide of a game with a few good shots in the right situation. Compared to the Onager, the Siege Onager has more health, damage, and pierce armor, but perhaps more importantly has a larger blast radius, making shots harder to dodge and able to hit more targets.

Upgrading to Siege Onager helps even out the playing field against one of the Mangonel-line's main weakness, the Bombard Cannon, to some extent. The reason for this is that the Siege Onager needs two attacks from a Bombard Cannon to be taken down, but can kill a Bombard Cannon in one full shot, while for the standard Onager it is the other way around. The large drawback of the much shorter range compared to the Bombard Cannon still remains however, so considering equal micromanagement skills and numbers, the Bombard Cannons should still come out on top. Another point to consider is invested resources: While the initial Siege Onager upgrade is very expensive, Bombard Cannons only require Chemistry (which is also useful for other ranged units), but Siege Onagers themselves are cheaper than Bombard Cannons, so in small numbers the Bombard Cannon is cheaper, but the higher the production numbers go, the more it evens out, until the cost of the Bombard Cannons actually surpasses the cost of Siege Onagers.

Siege Onagers are able to cut down trees, making them valuable in maps with large areas of forests like Black Forest by enabling to the player to attack from behind a forest.

Comparison among civilizations[]

Most civilizations with Siege Onagers have Siege Engineers, as well as some bonus for their Siege Onagers. The only exceptions for Siege Engineers are Malians, Cumans, and Dravidians. The Malians can research Chemistry 80% faster, but Chemistry is effectively useless for the unit. The Bulgarians do not have bonuses for their Siege Onagers either, but they research the Onager and Siege Onager upgrades for -50% food, which means that they have the fastest-appearing Siege Onagers in-game.

As for the other civilizations and their bonuses:

Civilization Team bonus Civilization bonus UniqueTechCastle-DE Unique technology UniqueTechImperialDE Unique technology
Aztecs AoE2 Aztecs Created 11% faster
Celts AoE2 Celts Created 20% faster Fires 25% faster +40% HP
Dravidians AoE2 Dravidians Cost -33% wood
Ethiopians AoE2 Ethiopians +0.45 blast radius
Koreans AoE2 Koreans Minimum range reduced to 1 +1 range
Mongols AoE2 Mongols Moves 50% faster
Saracens AoE2 Saracens +15% attack
Sicilians AoE2 Sicilians Resists conversion
Slavs AoE2 Slavs Costs -15%
Teutons AoE2 Teutons Resists conversion +4 melee armor

Further statistics[]

Unit strengths and weaknesses
Strong vs. Buildings, archers, siege weapons except Bombard Cannons, units in dense formations
Weak vs. Fast moving melee units especially Magyar Huszars and Elite Eagle Warriors, Mangudai, Bombard Cannons, Monks with Block Printing and Redemption
Hit points UniqueTechImperialDE Furor Celtica (+40%, Celts only)
Attack SiegeEngineersDE Siege Engineers (+20% attack against buildings)
ChemistryDE Chemistry (+1)
UniqueTechImperialDE Torsion Engines (increases blast damage radius by 0.45, Ethiopians only)
UniqueTechImperialDE Counterweights (+15% attack, Saracens only)
Range SiegeEngineersDE Siege Engineers (+1)
UniqueTechImperialDE Shinkichon (+1, Koreans only)
Armor UniqueTechCastle-DE Ironclad (+4/+0, Teutons only)
Movement speed UniqueTechImperialDE Drill (+50%, Mongols only)
Conversion defense Devotion icon AoE2DE Devotion (+1 min, +1 max)
FaithDE Faith (+4 min, +4 max)
HeresyDE Heresy (die upon getting converted)
UniqueTechCastle-DE First Crusade (+4 min, +4 max, Sicilians only)

Civilization bonuses[]

  • Aztecs AoE2 Aztecs: Siege Onagers are created 11% faster.
  • Celts AoE2 Celts: Siege Onagers fire 25% faster. Siege Onagers can convert herdable animals even if enemy units are next to them.
  • Dravidians AoE2 Dravidians: Siege Onagers cost -33% wood.
  • Georgians AoE2 Georgians: Siege Onagers receive -20% damage (-40% instead of -25%) when fighting from higher elevation.
  • Slavs AoE2 Slavs: Siege Onagers are 15% cheaper.

Team bonuses[]


AoE2-DLCicon-0 The Age of Kings[]

  • Siege Onagers move at a speed of 0.5.
  • Projectiles move at 2.9 tiles/s. Secondary projectiles without Chemistry move at 3.0.
  • Primary and secondary projectiles have an arc of 0.6 and 0.4 respectively.
  • Siege Onagers do not deal attack bonus against siege weapons.

AoE2-DLCicon-1 The Conquerors[]

  • Siege Onagers move at a speed of 0.6.
  • Siege Onagers deal +12 bonus damage against siege weapons.
  • Projectiles without and with Chemistry move at 3.5 and 2.9 tiles/s respectively.
  • All projectiles have an arc of 0.4 respectively.
  • Siege Onagers do not auto-attack if it may harm friendly units.
  • Heresy introduced.
  • Celts AoE2 Celts: Furor Celtica introduced. It gives Siege Onagers +50% hit points.
  • Mongols AoE2 Mongols: Drill introduced.
  • Koreans AoE2 Koreans: Shinkichon initially gives Siege Onagers +2 range. With patch 1.0b, the effect was reduced to +1.
  • Koreans AoE2 Koreans (team bonus): Siege Onagers have +1 range.

AoE2-DLCicon-2 The Forgotten[]

  • All projectiles move at 3.5 tiles/s.
  • Celts AoE2 Celts: Furor Celtica gives +40% hit points to Siege Onagers.
  • Teutons AoE2 Teutons: Ironclad introduced.
  • Koreans AoE2 Koreans (team bonus): Siege Onagers minimum range reduced by 1 (instead of +1 range).

AoEIIDE icon Definitive Edition[]

  • Koreans AoE2 Koreans (team bonus): Siege Onagers minimum range reduced by 2.

AoE2Icon-LordsWest Lords of the West[]

  • Sicilians AoE2 Sicilians: Initially, cannot train Siege Onager. With update 47820, they get access to the Siege Onager.

Dawn of the Dukes icon Dawn of the Dukes[]

AoE2Icon-DynastiesIndia Dynasties of India[]

AoE2Icon-ReturnRome Return of Rome[]

  • Siege Onager anti-Heavy siege attack decreased (+75 → +50).


The siege onager was the largest upgrade of the onager line of weapons. It had the longest range and did the most damage.
Age of Empires II manual


  • In the ancient Roman Empire, Onagers were designed to be used against lightly fortified towns, and massive armies, and thus the upgrade of this, armed the Onager with metal plates, were built twice the size and could fire medium and even large boulders to weaken walls that rams were not able to access.
  • The total cost to upgrade Mangonels to Siege Onagers is 2,250 food, 1,500 gold, making Mangonels the most expensive units to upgrade.
  • Despite the description given in the manual for the Siege Onager, it does not have any additional range over the Onager.
  • Despite the description in-game before the Definitive Edition, viz "used to attack a small mass of units", the unit gets better as the enemy army increases in numbers.
  • Before The African Kingdoms was released, the Siege Onager was the most exclusive unit in the game, i.e. no other unit was available to fewer different civilizations. With the introduction of The African Kingdoms, however, that title was lost to the Paladin. With the release of the Definitive Edition, however, the Siege Onager is tied with the Paladin as the most exclusive unit in the game. With update 36906, that title was won again by the Paladin. With Burgundians introduced, it is now tied again. With the Sicilians gaining access to the Siege Onager in update 47820, the Paladin has won the title again.
    • Coincidentally, the four civilizations that have access to the Siege Onager in The Age of Kings are playable in the campaigns.
  • None of the civilizations in Rise of the Rajas or Dawn of the Dukes have access to it. The former result in the condition that none of the Southeast Asian civilizations have access to Siege Onager. At the release of Lords of the West, none of the two civilizations in Lords of the West had access to the Siege Onager either; However, the Sicilians have access to the Siege Onager since update 47820.
  • Both African civilizations have access to Siege Onager.
  • During development, the Mangonel-line could attack ground to destroy all resources, as remarked by Sandy Petersen. The feature was removed for resources but not for trees, to make Black Forest games "less boring".
  • It is unsure when the Mangonel-line was changed to directly attack trees instead of only attacking ground.
  • The Dravidians are the only Siege Onager civilization which has a bonus for them, but does not have Siege Engineers.


Units in Age of Empires II
CivilianMaleVillDE Villager · Tradecart aoe2DE Trade Cart · FishingShipDE Fishing Ship · Trade cog aoe2DE Trade Cog · King eu aoe2DE King
ReligiousMonk aoe2DE Monk
InfantryMilitiaDE Militia · Manatarms aoe2DE Man-at-Arms · Longswordsman aoe2DE Long Swordsman · Twohanded aoe2DE Two-Handed Swordsman · Champion aoe2DE Champion
Spearman aoe2DE Spearman · Aoe2-infantry-2-pikeman Pikeman · Halberdier aoe2DE Halberdier
Eaglescout aoe2DE Eagle Scout · Eaglewarrior aoe2DE Eagle Warrior · EliteEaglewarrior aoe2DE Elite Eagle Warrior
ArcherArcher aoe2DE Archer · Crossbowman aoe2DE Crossbowman · Arbalester aoe2DE Arbalester
Skirmisher aoe2DE Skirmisher · Elite skirmisher aoe2DE Elite Skirmisher
Hand cannoneer aoe2DE Hand Cannoneer
Cavalryarcher aoe2DE Cavalry Archer · Heavycavalryarcher aoe2de Heavy Cavalry Archer
Aoe2de DOI elephant archer icon Elephant Archer · ElephantArcherIcon-DE Elite Elephant Archer
CavalryScoutcavalry aoe2DE Scout Cavalry · Lightcavalry aoe2DE Light Cavalry · Hussar aoe2DE Hussar
Knight aoe2DE Knight · Cavalier aoe2DE Cavalier · Paladin aoe2DE Paladin
Camelrider aoe2DE Camel Rider · Aoe2 heavycamelriderDE Heavy Camel Rider
Battle elephant aoe2DE Battle Elephant · Elite battle elephant aoe2DE Elite Battle Elephant
Steppelancericon Steppe Lancer · Elitesteppelancericon Elite Steppe Lancer
Xolotlicon Xolotl Warrior
AoE2DE Armored Elephant icon Armored Elephant · AoE2DE Siege Elephant icon Siege Elephant
SiegeBattering ram aoe2DE Battering Ram · Capped ram aoe2DE Capped Ram · Siege ram aoe2DE Siege Ram
Mangonel aoe2DE Mangonel · Onager aoe2DE Onager · Siege onager aoe2DE Siege Onager
Scorpion aoe2DE Scorpion · Heavyscorpion aoe2DE Heavy Scorpion
Bombard cannon aoe2DE Bombard Cannon
Trebuchet aoe2DE Trebuchet
Petard aoe2DE Petard
Siegetower aoe2DE Siege Tower
War shipTransportship aoe2DE Transport Ship
Galley aoe2DE Galley · War galley aoe2DE War Galley · Galleon aoe2DE Galleon
Fire galley aoe2DE Fire Galley · Fireship aoe2DE Fire Ship · Fastfireship aoe2DE Fast Fire Ship
Demoraft aoe2DE Demolition Raft · Demoship aoe2DE Demolition Ship · Heavydemoship aoe2de Heavy Demolition Ship
Cannon galleon aoe2DE Cannon Galleon · Elite cannon galleon aoe2de Elite Cannon Galleon
AoE2 Dromon Dromon
ReligiousMissionaryIcon-DE Missionary · AoE2 WarriorPriest Warrior Priest
InfantryBerserkIcon-DE Berserk · Aoe2de Chakram Chakram Thrower · CondottieroIcon-DE Condottiero · Aoe2-icon-flemish-militia Flemish Militia · GbetoIcon-DE Gbeto · Aoe2de Ghulam Ghulam · HuskarlIcon-DE Huskarl · JaguarWarriorIcon-DE Jaguar Warrior · KamayukIcon-DE Kamayuk · Karambitwarrioricon-DE Karambit Warrior · AoE2 DE Legionary new icon Legionary · Aoe2-icon--obuch Obuch · SamuraiIcon-DE Samurai · Aoe2-icon-serjeant Serjeant · Shotelwarrioricon-DE Shotel Warrior · TeutonicKnightIcon-DE Teutonic Knight · ThrowingAxemanIcon-DE Throwing Axeman · Aoe2de Urumi Urumi Swordsman · AoE2 WarriorPriest Warrior Priest · WoadRaiderIcon-DE Woad Raider
ArcherArambaiicon-DE Arambai · CamelArcherIcon-DE Camel Archer · ChukoNuIcon-DE Chu Ko Nu · AoE2 CompositeBowman Composite Bowman · ConquistadorIcon-DE Conquistador · GenitourIcon-DE Genitour · GenoeseCrossbowmanIcon-DE Genoese Crossbowman · Imperialskirmishericon-DE Imperial Skirmisher · JanissaryIcon-DE Janissary · Kipchakicon Kipchak · LongbowmanIcon-DE Longbowman · MangudaiIcon-DE Mangudai · PlumedArcherIcon-DE Plumed Archer · Aoe2de ratha ranged Ranged Ratha · Rattanarchericon-DE Rattan Archer · SlingerIcon-DE Slinger · WarWagonIcon-DE War Wagon
CavalryBallistaelephanticon-DE Ballista Elephant · BoyarIcon-DE Boyar · Aoe2de camel scout Camel Scout · CataphractIcon-DE Cataphract · Aoe2de roman unique centurion icon Centurion · Aoe2-icon-coustillier Coustillier · Flaming camel icon Flaming Camel · ImperialCamelRiderIcon-DE Imperial Camel Rider · Keshikicon Keshik · Konnikicon Konnik · Leitisicon Leitis · MagyarHuszarIcon-DE Magyar Huszar · MamelukeIcon-DE Mameluke · AoE2 Monaspa Monaspa · Aoe2de ratha melee Melee Ratha · AoE2 Savar Savar · Aoe2de shrivamsha rider Shrivamsha Rider · TarkanIcon-DE Tarkan · WarElephantIcon-DE War Elephant · Aoe2-icon-winged-hussar Winged Hussar
SiegeAoe2-icon--houfnice Houfnice · Aoe2-icon-hussite-wagon Hussite Wagon · OrganGunIcon-DE Organ Gun
War shipCaravelIcon-DE Caravel · LongboatIcon-DE Longboat · Aoe2de Thirisadai Thirisadai · TurtleShipIcon-DE Turtle Ship