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Age of Wonders 4 Dev Diary #14 – Sieges

Greetings again future Conquerors! Welcome to another Development Journal! I’m Bas, who also wrote the Development Journal on Ancient Wonders. This time, we’re not looking at cracking open Ancient Wonders for treasure, but rather, we’ll be looking at cracking open Cities! I’ll be talking about the new Siege System in Age of Wonders 4!


Cities in Age of Wonders are the core of an empire’s economy, which in turn fuels their war machine. Having one of your cities taken is therefore a huge blow and in the case of someone’s capital, could even result in a player losing or winning the game. 

In Age of Wonders 3 players had to make sure they always had armies close to vulnerable cities as they were not defended by default. In Planetfall, we had garrisons to make sure cities and sector bases were defended at all times. However, it added a lot of extra units to already huge fights with exactly the same layout, making players tired of fighting these kinds of battles and auto-resolving them. It also couldn’t stop a player from launching surprise attacks and overwhelming the garrison in a single turn.

Age of Wonders 4 offered us an opportunity to sit down to tackle and improve upon these points. Our aim was to give defenders time to respond, to add more variety to City battles, and to not use the Garrison system to cut down on the amount of units involved in battle.

In the end, we came up with the Siege system, where defending players can invest in structures that help to delay attackers and affect the battle map. Attackers in turn have to lay siege to the cities for multiple turns in the world map where they can invest in Siege Projects to bring siege engines to the battle, or otherwise counter some of the defenses the city has, before they can launch a final decisive battle!


Let’s go back to those defensive structures for a minute, we’ll get into the siege itself later:

Some of the coolest and most appreciated parts of Age of Wonders 3 and Planetfall’s City battles were that certain structures such as turrets would be represented in battle. In Age of Wonders 4, we tried to go a step further! We now have several categories of Defense Structures that will be represented in the Siege battle:

  • Wall Defense Structures will contribute the most to Fortification Health (more on that later), and at least one wall must be built in a city to add the requirement for attackers to siege it. Furthermore, they are represented as different obstacles in combat! Palisade walls are wooden obstacles with low health, but Stone walls are Fortified obstacles with a lot of health that are tricky to take down. The latter also will have less breaches at the start of combat. Making it easier to funnel the attacker down killzones!


  • Tower Defense Structures are the turrets of Planetfall. They spawn units during combat alongside the walls with incredible range and will automatically fire upon attacking units. There are even some more special Towers that instead cast magical buffs or even heal nearby defending units.

  • Battlement Defense Structures create special obstacles on the positions just behind the wall that benefit the Defender in some way. They often buff Ranged attacks, and can specialize further in buffing Magical or Physical ranged attacks. Such as units gaining extra range, more accuracy, or straight up setting target locations on fire with their attacks!

  • Support Defense Structures add special modifiers to the combat, often in the form of Combat Enchantments! They can do things like spawn Caltrop obstacles in front of the walls. Forcing attackers to go through Slowing and Sharp terrain which inflicts bleeding on them as they try to pile through the breaches!


All defensive structures also add Fortification Health, which is displayed beneath city banners and determines the rough amount of time attackers will need to spend sieging the city before they can launch their attack. 

This is visible to everyone as long as you’ve discovered the city, so it’s handy to scout out enemy cities before moving in to know what kind of time investment you’ll need to make! If you have a good eye, you can even spot the kind of walls they have by looking at the city model.


Alright, enough about the defender preparing. Let’s look at the attacking side!

You can start a siege simply by initiating an attack or move order on a hostile walled city! You must do this with at least one hero available in the army who will be leading the siege (Marauders are exempt from this rule, yep, that’s right, infestation stacks can and will siege you!).

A prompt will ask you if you wish to start a siege, and a time estimation in turns is given. Pressing Start will begin your siege!


In the first turn of sieging, you have a nice overview of the Fortification Health of the city and its defense structures. Every turn during a siege, the Fortification Health (wall icon) will be diminished by the amount of Fortification Damage (broken wall icon) you deal. Until Fortification Health reaches 0 at which point you can initiate an attack!

Fortification Damage per turn is determined by:

  • A base value of 10 damage per turn

  • Units with Siege Breaker in besieging armies, such as Giants and Iron Golems

  • Siege Projects active during the siege

Siege Projects are specific actions the attacker wants to undertake to take out certain defenses of the attacker, speed up the siege, construct siege engines or employ something else like stealing population from the besieged city, they often come at a cost and take up a Siege Project slots, which you can get more of through empire skills.

As the attacker you can select which Siege Projects you wish to undertake only in the first turn of the siege, at which point they will be locked as your armies are executing your plans. In the case of Siege Projects that speed up a siege, they will contribute extra Fortification Damage done per turn. 

This was set up in a way to have siege projects be more effective when a city is heavily fortified, creating a different balance between cost and effect per siege.

Headlong Assault for example, which contributes +5 Fortification Damage on top of the base 10 Fortification Damage, will reduce siege time with a city of 30 Fortification Health by 1 turn. But in a city with 120 Fortification Health, it can reduce it by 5 turns!

All empires have access to a multitude of standard Siege Projects, but more can be obtained through tomes or even Ancient Wonders. Such as a displacing effect from the Tome of Mayhem’s Sow Confusion siege project, or the Soul Siphon siege project from Tome of the Reaper to gain extra souls upon completion of the siege and gain Zombie units in combat.


While a siege is progressing, if the attacker has brought multiple armies, they don’t have to simply wait around the walls for the timer to run out. Reserve armies can simply run around the domain, scouting for hidden relief forces on the way or pillaging province improvements, especially Special Province Improvements like Teleporters and Spell Jammers you may want to take out while besieging to make sure no nasty surprises will await you once in battle.

Be aware though that this leaves the defender with opportunities for counter attacks by catching you outside of reinforcement range! This lets sieges be more dynamic.


Let’s quickly go back to the Defender, while their city is under siege, it suffers a hefty -50% penalty on all resource incomes except Draft, and cannot produce any City Structures during a siege either! This incentivizes defenders to take action instead of just waiting for the very last moment. Luckily, there are ways for defenders to prepare while a siege is going on.

A defender can see what Siege Projects are being taken against the city and how long the siege lasts. They can still recruit units in the city, rallying a quick militia to hold out against defenders to discourage the attacker from splitting up or even counter attack. 

While this is going on, Defenders can also rally defenders from other places, Rally of the Lieges and Empire Rites can often prove handy in these situations to raise a quick army. Defenders can still freely move defenders in and out of the city. 

We’ve tried restricting movement for defenders in besieged cities but found it too restrictive for the defenders to raise a proper defense. This allows defenders to actually undertake successful relief efforts and keeps attackers more on their toes.


Once the timer has run out, the Fortification Health depleted to 0, the attacker can initiate the battle! The battle map is a lot more grim and ridden with destruction than previous city battle maps. After all, a siege has now taken place and breaches have appeared in the walls! These breaches form perfect funnels for the defender to exploit. But the attacker can, if they brought the right units, spells or siege engines, create their own additional breaches by attacking the walls!

Next to that, City Defense Structures and Siege Projects can also affect the battle map as described! Siege battles can now really look different depending on what has been undertaken by both defender and attacker.


As for the battlemap. It’s always challenging to create a city map that is balanced yet not samey, look grimey yet not unreadable. What me and Sara have done primarily is realize a vision of a battered city wall, a last bastion of defense, by littering the battlefield with broken remnants of the city, with plenty of muddy puddles and the occasional corpse fallen from previous attempts at breaching. 

Most of these are decorative to create enough space for the players’ massive armies. And we’ve created custom lighting to contrast the units and line of wall obstacles from the background decoration!

Speaking off, Wall obstacles count as cover, making targets count as Obscured when they shoot over them. However, if defending units stand on the intact battlement hexes, they get to ignore Obscured as they have the high ground!


Next to this, breaches will already appear at the start of battle, unlike in previous Age of Wonders games, as you’ve been besieging these cities for a while. These are generated in a controlled way to create killzones for defenders, but with the occasional unfortunate breach that allows fast units to break through quickly!

If you’ve brought siege engines or units with Demolisher, you can also easily create new breaches in the walls that are still intact, or destroy enemy towers or battlements if they have any. 


So, there you have it! Sieges do away with the micro-intense cat and mouse movements of the old games. Instead creating more trust for players to venture out with their armies. Giving them enough time to come back to, or raise new armies in defense. While attackers can employ tools to counter defenses or instead aim for more economic damage than outright city conquest. 

I hope to see and hear of many epic siege battles deciding the fate of empires on the brink of destruction or victory. Don’t forget to lock your gates when you get to play Age of Wonders 4!