Wars in Looming gaia history?
I think realistically there have been thousands upon thousands of wars in Gaia's history, both big and small, so I'll narrow it down and talk about some of the most notable ones. I'll try to keep each entry here short, but if you want more information on any of them just let me know and I can make a separate post.
Gold River War: Yerim-Mor Kingdom was once the richest of the Great Kingdoms. One day a massive earthquake struck the land, bringing great devastation all across this kingdom. The earthquake also exposed a ton of gold in the Sunglow River, the lifeblood of Yerim-Mor. This river was renamed "Gold River" as Matuzu Kingdom moved in to take it all for itself, kicking the Yerim-Mor people down while they were still reeling from the disaster.
Matuzu really took advantage of the situation, using it as an opportunity to occupy chunks of Yerim-Mor's territory and steal its resources. This event was known as the "Gold River War". Yerim-Mor tried to defend itself, but it was no match, as other entities such as the Divine of Hate moved in to take advantage as well. It went from being the richest kingdom to the very poorest. The effects of this war are still very apparent today.
The Ogre Wars: This was a series of many battles fought between the ancient Evangelites and the native ogre tribes of Noalen. The Evangelites had successfully conquered or assimilated all the other peoples of this land, but they were struggling with the ogres, who just seemed to be too powerful. Long story short, Evangeline was not successful. They sunk a lot of lives and resources into trying to conquer these ogres, and in the end, the ogrish tribes still stand today in the middle of Evangelite territory as independent little nations. The Evangelites just leave them alone, and in return, the ogres keep to themselves too.
Because they have not been conquered, these ogrish tribes are not bound by Evangelite law. They have their own laws within their walls. This means that escaped Evangelite slaves, refugees, and defecting soldiers often seek these tribes as temporary safe havens while they make the journey to other kingdoms. As you can imagine, this really irritates the Evangelite government, but there isn't much they can do about it while they're stuck in this ongoing war with Folkvar. Which brings me to my next war...
The Evangeline-Folkvar War: You can read more about this one in the main Evangeline and Folkvar articles, but basically Evangeline's slavery laws led to a civil war, in which many citizens and slaves defected from the kingdom and founded their own kingdom, called Folkvar. Folkvar Kingdom has been at war with Evangeline since its conception, as its people continue to fight for their own freedom from Evangeline even today.
Sovereign's Bloodwave: This wasn't exactly a war in itself, but it was the event that incited the war between Zareen Empire and the Aquarian Alliance. Sovereign pleaded with Zareen Empire to stop polluting the sea and his his people for long enough, and he decided it was time to take drastic measures to be heard. So, he sent battalions to capture thousands of children from Zareen's coastal territories. These children were violently executed in the sea and their corpses were carried by a great magical wave, directed towards the city of Driza.
The wave devastated the city with a flood that left a grisly mess when the waters receded. The streets were choked with sewage, trash, and the severed body parts of innocent Zareenite children from all over the empire. The aftermath of this led to disease spread, and the epidemics caused even more death and destruction for several years afterwards, not to mention the emotional toll on all who witnessed such a horror...which was the entire megapopulated city of Driza.
Sovereign's message was heard loud and clear, but the response was not what he hoped. Instead of meeting his demands, the Zareenites doubled down on their pollutive ways and officially declared war upon his nation.
The Battle of Driza: Poor Driza can't catch a break, can it? That's because this city is a major industry hub for Zareen Empire, and that makes it a big target for enemy attacks. It produces much of the empire's energy with a massive dirty fuel plant, and the waste from this plant is dumped right into the sea. Sovereign once sent a few thousand dorikori (brainwashed mermaid soldiers) on a suicide mission to bomb this plant and take down Zareen's power grid, in preparation for an even bigger attack. This battle was a major plot point in the story "Chains of Melody".
(((SPOILERS: the attack failed because a spy from the Oceanic Resistance tipped off the Zareenite military ahead of time, giving them ample time to intercept it. The result? Thousands of dorikori lie dead for no reason. Smooth move there, Sovereign...)
The Matuzu-Etios War: There is more info about this in the main Etios and Matuzu articles. The short of it is, Matuzu Kingdom once had a ruthless fae regime who decided that all gaians were inferior species who should be enslaved. The kingdom's gaians were like "fuck that" and put up a much bigger fight than the regime expected. Matuzan gaians organized a mass exodus to the southern, more undeveloped part of the kingdom and colonized it for themselves. They formed their own kingdom called Etios Nation, a place where gaians dominate and fae are not allowed. Matuzu has been trying to reclaim this land from Etios ever since, but has not been successful...mostly because Matuzu can't mind its own business and has like 2-3 other wars going on at any given time. They really shot themselves in the foot with this one, as the two kingdoms are still at war even today and there is no sign of peace anywhere near the horizon.
There are definitely more, but that's all I can think of at the moment. I might add some more later.