Europa Universalis IV - Mod Spotlight - Mesoamerican Expansion Mod, 2023

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Embark on a Fascinating Journey: Discovering Mesoamerica's Rich History through the Mesoamerican Expansion Mod Created as part of the 2023 EU4 Modathon!​

Hello Everyone,

I am Minnator, one of the creators of the Mesoamerican Expansion, a mod that completely overhauls the Central American region also known as Mesoamerica.
I am happy to welcome you to a mod that was created during the 2023 Modathon and thus created in a very strict time frame of two weeks. Even though time was scarce the mod is filled with secrets, flavor and a very interesting story to its creation.

In this mod spotlight I not only want to show you around the content we have done, but also showcase how we did it during the Modathon and how you can take part in the next Modathon yourself. But more about that later.


Let’s start with a rough overview of what we have for you today:​

  • How the mod came to be
  • Map changes
  • Reworked Nahuatl religion
  • New government reforms
  • New generic mission tree
  • New Aztec mission tree
  • New buildings
  • New government mechanics
  • New disaster
  • New estate privileges
  • Three new music tracks
  • The next Modathon

How the mod came to be​

A few years ago a close friend of mine found himself playing the natives in the new world, but since they seriously lacked content, we decided to sit down and make a mod to enrich the area with gameplay mechanics we thought could make this type of gameplay more interesting, and better yet, more fun to play.
This summer, Khyler messaged me about the upcoming Modathon, and the choice to participate was easily made. After some thought, we decided to revisit the concept that had once introduced us to the EU4 modding community in the first place; New World Natives. This coincided nicely with the idea of another Modder by the name of Varaan, who was searching for contributors to a Meso-American mod. And just like that, the concept and team for our mod were set, ready for the 2023 Modathon.

During our team meeting, we each took on roles that played to our strengths: Varaan focused on missions, Khyler on the soundtrack, I handled map edits, government mechanics, disasters, and other smaller tasks, and Verinity Void provided historical text whenever necessary.

Our aim with the mod was to give immersive, yet challenging, gameplay to the Aztec nation as well as the countries surrounding them. There were also plans to do the same for the Maya, but sadly time ran out and we had to cut it from the finished mod.

Map Changes​

Regarding the vanilla Map in the Mesoamerican region we quickly noticed that there were too few provinces to ensure an entertaining gameplay until the colonizers arrived. Thus we decided to add a total of 17 new provinces to the map. As there is not a lot of documentation on how this region was split up in the 15th century we decided to settle on a relatively accurate map that displayed part of the region and added provinces named and located after cities and settlements from said map.
All in the image highlighted provinces where added


Reworked Nahuatl religion​

In vanilla the Nahuatl faith is represented using religious reforms which are accompanied by the Doom mechanic. This usually makes for a tedious and one-dimensional gameplay forcing the player to continuously keep an eye on their doom, losing all vassals five times until the religion can be reformed.
We wanted a completely different system that enhanced the existing Doom, removed the religious reforms and added fun and entertaining ways to manage the Doom. We used the now moddable government mechanics to display and visualize doom while the options to handle it are spread across the entire mod.


But that's not all. To further enhance the experience we decided to use the Religious Schools system that is found in the Muslim religion group in vanilla EU4.



Tezcatlipoca was one of the major gods in the Aztec religion, playing a significant role in their cosmology and mythology. Often referred to as the "Smoking Mirror", Tezcatlipoca was associated with various aspects including creation, destruction, destiny, sorcery, and change. He held a complex and dual nature, embodying both light and darkness, creation and destruction.


Tlaloc was the Aztec god of rain, fertility, and agriculture. He was often portrayed with goggle-like eyes and fangs. Tlaloc was crucial to agricultural success, as rain was essential for crop growth. Offerings and ceremonies were made to appease Tlaloc and secure his favor, especially during the rainy season.



Quetzalcoatl, known as the "Feathered Serpent", was a prominent Aztec deity associated with wisdom, creation, and wind. He was depicted as a feathered serpent or a human figure with a bearded face. Quetzalcoatl was often seen as a bringer of civilization and culture, associated with arts, learning, and rulership. His rivalry with Tezcatlipoca was central to Aztec mythology, representing the balance of opposing forces in the world



Huitzilopochtli was the Aztec god of war and the sun, often depicted as a hummingbird or an eagle. He was a central figure in Aztec mythology and society, associated with military prowess and protection. Human sacrifices were dedicated to him to ensure victory in battle and the continuation of the sun's journey across the sky


New government reforms​

With the aim to represent the culture, politics and diplomatic situation of the Mesoamerican realm back in 1444 and the following centuries until their downfall to the colonizers we created several unique government reforms. Almost all of the added reforms are deeply intertwined with our government mechanics such as the Doom, Colonial Influence and the Power Struggle. Further down in the Spotlight we will see that a disaster is also controlled and set by a government reform. Here I will present to you a few of my personal favorites:


But there is one Diplomatic relation you might have heard of: The Triple Alliance. We also tried to show it as accurately as possible by our own interpretation of it:


New generic mission tree​

As this mod was made during the Modathon 2023 we had a very limited timeframe of 14 days to accomplish our goals. This means that extensive mission trees for multiple countries was just not in the budget, so we decided to instead create an engaging 38 missions long generic mission tree that is accessible to all Nahuatl nations in the mesoamerican region.

This generic mission tree is different from most vanilla generic missions. It not only has some basic conquest and some simple build up mission. It hosts options to improve your already existing realm, battle the colonizers, do a sunset invasion and is even going as far as to give you the chance to take revenge for what the colonizers did to you and your people by sacrificing the pope or the emperor of China.




New Aztec mission tree​

Given our very limited time of only 14(!) days to produce a fully functional mod, we decided that we could only focus on one country’s unique mission tree, and with their rich history our choice obviously was to create said mission tree for the Aztecs. When Varaan proposed to make a 54-mission tree for the Aztecs in this short time I thought he was crazy! However, he surprised us all by not only delivering on that promise but also completing the additional generic mission tree within that time. This was possible only due to modding tools created by the community but more on that later.
So let’s dive into the Aztec Mission tree and see what it has to offer!


With EU4 only having the mesoamerican region colonized at the start of the game and the surrounding regions only populated by migratory tribes, we wanted to offer the player an option to properly expand past the borders of Mesoamerica. As we deemed colonists unfitting, we settled on giving access to the Siberian frontier mechanic for a limited timeframe that could be regained, for a price.



In the next part of the mission tree we will focus on the development of infrastructure.
Instead of giving static and repetitive rewards we focused on giving bonuses to already existing modifiers and mechanics or giving the player a choice by completing missions in different ways.
Here a few highlights:

The next portion focuses on historic structures of Aztec Importance, as well as the historic production of goods.
We also expanded on an alternate path Aztec history could have taken.

This is just a preview of what is waiting for you!

The finishing touch to the mission tree obviously is how to handle the colonizers. There not only is a disaster as shown further in the Spotlight, but also a bunch of alternative timeline missions such as enforcing your rule on the Christianity, the Emperor of China and even the Shogunate of Japan!
But all of these targets are far over the sea so that means we need to tame the oceans first before we can bring the fight to the colonizers themselves.
This struggle over supremacy on the seas is displayed extensively as well.
Instead of spoiling everything we have created for you I will just give you a small highlight of what is to come:


New Buildings​

As we reshaped the gameplay for the mesoamerican region we had the idea to introduce new buildings and modify existing ones to better fit our scope. Marked in red I highlighted the buildings we added and I also have a preview of what to expect:


Government Mechanics​

When the Modathon took place and we were creating our mod the beloved government mechanics had become moddable in the then latest patch. As they are a powerful and amazing tool to represent and manage historic values of a country or disasters we promptly used them for both.



When thinking of the Mesoamerican region in EU4 the first thing that comes to mind is the painful doom mechanic that poses a significant challenge. We set our aim to increase the experience in the region so we definitely had to do something about it.
So we converted it to a government mechanic, gave it some new textures and adapted all vanilla ways to handle doom to fit our representation of it.
Let's dive a bit more into how it works:

Doom represents how satisfied the gods are with you, and historically the Aztecs tried to calm their gods by sacrificing humans and their blood to worship them.
So we made it possible to sacrifice your ruler, pay people to sacrifice them, raid your neighbors to gather prisoners of war to sacrifice them, sacrifice your subjects ruler and heirs and finally, your heir, if your ruler is cruel.
There are also some special events and cases depending on your ruler that can cause either the gain of Doom or the loss.


Using the Sacrificial Raids casus belli, which can be obtained via one of the interactions in the Doom mechanic, will enable a special peace treaty:


Colonial Influence​


But Doom will not be the only stepping stone on your way to supremacy. There also is the so-called Colonial Influence.
Colonial Influence will become available once you have reformed your religion and the first colonizing nation has a colony on your border.
This will slowly make the bar load up and if it reaches 100% it will trigger the disaster Struggle for Power, which I will address in a second, and destroy the gold price for several years as your mines are being looted by the colonizers.
There are two interactions to try and handle Colonial Influence. Both of them focus on actively reducing government power. Of course, there are also a ton of events that will follow you and your way taking care of this threat.


As you are inevitably bound to succumb to the Colonial Influence, the Disaster “Struggle for Power” will start and show the last government mechanic I have for you today.

Struggle for Power​

The Power struggle will be announced by several events leading up to it.


On the left is the disaster itself and on the right is the government mechanic
The Disaster itself has two possible outcomes which makes it unique.
As Shown in the tooltip you can either win or lose. And which case will happen is determined by the so-called Scales Weighing. The last Government mechanic I added.
The disaster is short but hurtful but if you are up for a challenge, you can decide to make it even harder so that it might yield a better reward upon ending.

Over the course of the next few months several events will fire until your scales weighing either reaches -100 or 100. Depending on what you reach will you either lose or win which will affect the “reward” you will be given.
Here are some examples what the events will look like:

Estate Privileges​

I also have some new estate privileges for you that are meant to intertwine with the other mechanics we introduced and give them some more depth.
Some of these privileges will be locked upon game start but will become available once certain requirements or missions are fulfilled.

Music Tracks​

So, Hello there, Kyhler here (The Music guy). To top off the experience and to stand out amongst the other mods, we decided to make 3 completely new music tracks, which was a challenge in the timespan of two weeks. Something that made it harder than it was just being two weeks was that I started the creation later, since we had mentioned the idea before the project, but never really decided on if we should do the music part of it. But I decided to just do it a day or two in.

The tracks in general​

I won’t bore you all with the notation and theory side of it, but instead talk about how I was able to create the Mesoamerican feel and make them fit EU4 as well. To start off with all of them use ocarinas as the main instrument, all in different pitches. This was done since it after all was an instrument that the Aztecs and surrounding people had access to, but as all will notice brass and string instruments also accompany the pieces to give them a broader and more epic sort of sound. But time to take a closer look at each of the 3 pieces.


The City on The Lake​

“The City on the Lake” is what I see as the main theme of the mod. It starts off slow and calm but begins to pick to give the feel of your nation moving forward. Going from “simple” tribes to something more, a nation. A nation that has to compete with the rest of the world. Another way this is shown is in the use of instruments, so the western instruments are first introduced in the latter part of the piece where it picks up and is “introduced to the world”.

The Sixth Cradle​

This piece is the more percussion heavy one of the bunch, where the percussion plays a role to sound like the busy people of the Mesoamerican cradle, as in one would be able to hear them work and live there, as after all it is a birthplace of a civilisation just like Mesopotamia is. There are also a lot of different parts moving throughout the piece which really helps to drive home the “busy” feeling of a civilisation.

Enemies at our Shores​

Last but not least “Enemies at our Shores”. As the name suggests, this is the war piece, the one to signal war, but not just any war, a war for survival against the Europeans which is why the horns and violins take a more central role in the piece as a whole. It brims of war all the way through it really, since the start of it is a bass ocarina (made play impossible low for real world performance) with a single pitch sounding like a warning signal and then followed by a bass drum to sound like the beginnings of a march. And then after all of that we have the horns and contrabass/cellos on a half depressing melody but gives the feel of “we have to fight” when the horns get a few higher pitch notes off.

But that was all she wrote for the music and all that I had to say, hope you enjoyed the music (and the mod as a whole).

The Next Modathon​

Now I want to end this Mod Spotlight with an announcement. It has been almost half a year since the last Modathon, and seeing the success it had, I am happy to announce that the next one will take place in February. More information can be found on the Discord server!

The point of a modathon is that participants are allotted a certain time window to create a mod for one of the various categories that teams can sign up for, create teasers for them, and in the end, showcase your mod to everyone!
After the modding is complete the community votes to decide which mods they like per each category, as well as various overall awards (including an overall winner this time around)!

If you are interested in getting into EU4 modding and/or are looking for some tools to ease the process of it, feel free to join the Modathon Discord Server []

Now I hope you are as thrilled to either play the Mesoamerican Expansion or join the next Modathon!

If you are interested in checking out the Mesoamerican Expansion live, do so by downloading the mod:
If you have any questions for us feel free to ask then in the comment section of the Mod or on the Modathon Discord server!

Have a good Day!


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  • 23Like
  • 7Love
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This is some high quality work here. Like I'm pretty confident that if you just posted some of these screenshots online without context and told people they were leaked images of upcoming DLC a good number of people would probably believe you.
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Who made the new music?
  • 1Like
"We won't bore you with all the theory"
Me wanting to be bored by music theory.

Also this:

Screenshot 2023-12-18 at 4.23.31 PM.png
  • 2Haha
Add me on discord and I can prove it I guess, my name is just "kyhler" there and I can show you my rank on the modathon server, you can also add me on steam where I'm also called Kyhler, just find me through the mod page since I'm listed on it
Edit: spelling mistakes
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Under the Tzintzuntzani Missions, "Strike Yokotan", "Land of Pyramids", those are images of South Indian Gopurams. Seems to be an odd image choice for Central American Pyramids. Haven't played much in the region before, but is there no Central American Pyramid image available?
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