| “ | 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[]
 Available
|
 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.
Tactics[]
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 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 |  Unique technology
|
 Unique technology
|
|---|---|---|---|---|
 Aztecs
|
Created 11% faster | |||
 Celts
|
Created 20% faster | Fires 25% faster | +40% HP | |
 Dravidians
|
Cost -33% wood | |||
 Ethiopians
|
+0.45 blast radius | |||
 Koreans
|
Minimum range reduced to 1 | +1 range | ||
 Mongols
|
Moves 50% faster | |||
 Saracens
|
+15% attack | |||
 Sicilians
|
Resists conversion | |||
 Slavs
|
Costs -15% | |||
 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 Eagle Warriors, Mangudai, Bombard Cannons, Monks with Block Printing and Redemption |
| Upgrades | |
| Hit points | Furor Celtica (+40%, Celts only)
|
| Attack |  Siege Engineers (+20% attack against buildings) Chemistry (+1) Torsion Engines (increases blast damage radius by 0.45, Ethiopians only) Counterweights (+15% attack, Saracens only)
|
| Range | Siege Engineers (+1) Shinkichon (+1, Koreans only)
|
| Armor | Ironclad (+4/+0, Teutons only)
|
| Movement Speed | Drill (+50%, Mongols only)
|
| Conversion defense |  Devotion (+1 min, +1 max) Faith (+4 min, +4 max) Heresy (die upon getting converted) First Crusade (+4 min, +4 max, Sicilians only)
|
Civilization bonuses[]
Aztecs: Siege Onagers are created 11% faster.- Celts: Siege Onagers fire 25% faster. Siege Onagers can convert herdable animals even if enemy units are next to them.
- Dravidians: Siege Onagers cost -33% wood.
- Georgians: Siege Onagers receive -20% damage (-40% instead of -25%) when fighting from higher elevation.
- Slavs: Siege Onagers are 15% cheaper.
Team bonuses[]
- Celts: Siege Onagers are created 20% faster.
- Koreans: Siege Onagers minimum range reduced to 1.
- Lithuanians: Researching Heresy, Devotion, and Faith is 20% faster.
- Malians: Researching Chemistry and Siege Engineers is 80% faster.
- Portuguese: Technologies that benefit Siege Onagers are researched 25% faster.
- Teutons: Siege Onagers are more resistant to conversion.
Changelog[]
The Age of Kings[]
- Researching Chemistry reduces the projectile speed from 3.5 to 2.9.
The Conquerors[]
- Siege Onager movement speed increased (0.5 → 0.6).
- Siege Onagers gain +12 bonus damage against siege weapons.
- Heresy introduced.
- Celts: Furor Celtica introduced. It gives Siege Onagers +50% hit points.
- Mongols: Drill introduced.
- Koreans: Shinkichon initially gives Siege Onagers +2 range. With patch 1.0b, the effect was reduced to +1.
- Koreans (team bonus): Siege Onagers have +1 range.
The Forgotten[]
- Researching Chemistry does not affect the projectile speed anymore.
- Celts: Furor Celtica gives +40% hit points to Siege Onagers.
- Teutons: Ironclad introduced.
- Koreans (team bonus): Siege Onager minimum range reduced by 1 (instead of +1 range).
Definitive Edition[]
- Koreans (team bonus): Siege Onager minimum range reduction increased (1 → 2).
Lords of the West[]
- Sicilians: Initially, cannot train Siege Onager. With update 47820, they get access to the Siege Onager.
Dawn of the Dukes[]
- Siege Onagers have +75 attack against the Heavy siege armor class.
Dynasties of India[]
- With update 61321, Siege Onagers are now resistant to armor-ignoring attacks, similarly to buildings.
- Saracens: Counterweights introduced.
Return of Rome[]
- Siege Onager anti-Heavy siege attack decreased (+75 → +50).
History[]
| “ | 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 | ||
Trivia[]
- 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.
- However, neither the Byzantines (Eastern Roman Empire) nor the Romans (Western Roman Empire) have access to the Siege Onager, despite being the Roman Empire's continuation.
- In medieval times, Mangonels and Trebuchets were used in sieges, as they proved to be more useful against large fortified walls.
- 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.
Gallery[]
