What is the biggest war YN have fought?

[Alpinumtia]

Not necessarily the bloodiest, but biggest in terms of mobilization of men and war material.

For Alpinumtia, it's the Third Corlaean War between the coalition consisting of the Confederation of Corlaea + the Kingdom of Equatoris versus Alpinumtia. During the decade long conflict (1997-2006) what was supposed to be a small regional conflict caused the mass mobilization of over ten million civilians and the usage of tactical nukes against each other. This led to the total destruction of Equatoris and Corlaea, however the utter devastation the war have caused for Alpinumtia cannot be understated. The region of West Corlaea is completely destroyed, however rebuilding efforts are under way.

[Remulia]

The third "Remulian-Hardarian" war...we had to fight, not only the Hardarians but also the Koln combine. Taking into consideration the Krants, this was the biggest war the Imperium had fought in all its history. Even the "Gryan-Remulian" war looks like a kid's game when you compare it to the RHWIII.

[Tsarstvo Alyaski]

As an extension of the Russian Empire, that would definitely be WW1, for obvious reasons, of course.
But, if we're talking strictly about Tsarstvo Alyaski, that would be it's sequel, WW2. They joined the United States of America a couple of months after Pearl Harbor, in the fight against the Empire of Japan. Still rather limited compared to the USA, Tsarstvo Alyaski did provide around 25,000 soldiers in the island hopping campaigns under a Alyaski Expedition force of the USA. The home army managed to defend Attu and Kiska island against a Japanese invasion, but that was all they saw.

[Ceannea]

Ceannea was an ally of the United States during the Second World War. The war involved the largest mobilization of Ceannean troops, with over 500,000 Ceanneans being in the military in both frontline and non-combative roles. Ceannean troops defended the archipelago against Japan during a 1942 invasion in the bloodiest battle in Ceannean history resulting in a pyrrhic victory in the capital city of Kingsborough; nearly the entire city was burned to the ground and over 60,000 Ceanneans lost their lives.

[Drusoria]

Drusoria was formed as an off-shoot of Germany in the Great War. When World War 2 came, the Drusorian Army were underequipped with aging equipment provided by the allies. When the blitzkrieg came, we quickly surrendered, with roughly two companies worth of trained soldiers who, along with the Home Guard, went underground, forming a partisan movement, attacking key targets. They formed a key part of the ally's assault to retake Drusoria, with the reformed Drusorian Army sending a volunteer force into Nazi Germany, the Drusorian Volunteer Division becoming one of the volunteer units with the highest kill counts, with many continuing to volunteer when the US retaliated against the Pearl Harbour attacks.

[Republica Federal de Catalunya]

I would say both WWs. Problaby the 2nd had a biggest impact.
Though We have fought in plenty huge ones as: 30 years war, Spanish Succession war, ottoman wars, Austrian Succession War, 7 years war, French revolutionary wars, Napoleonic Wars, etc. None has had the impact of the two above.

[Polish PR]

Second Arab-Israeli War (1 October 2015 - 26 June 2020). Also it was the bloodiest war, which Poland got fully involved in.

Casualties:

Military: 1 952 559 (including 108 130 Polish)
Civilian: 9 713 337

[Salzcovia]

Probably the Portuguese Colonial War, when Salzcovia supported the colonies with soldiers and supplies. In this war we lost 10.000 men, but our prestige grew a lot and we "won" the war. Yes, Salzcovia didn't participated of so much big wars.

[Falthonia]

For my nation, the alternate WW2 where the Falthonian Commune, with the Soviet Union, held Crimea for 5 months, encircled millions of Germans from Kiev to Riga and the Soviet-Falthonian Counterattack where the two nations invaded Warsaw, Berlin, Venice, Paris and Copenhagen.70% of the 15 million men of my country died from war, as POWs and in work camps.

[Molither]

Molither allied with Britain in WW2

[Novostia]

The War of the Western Alliance (December 2008 to May 2017)

The war was between Novostia against Darenos, Lexisuov, Uielao and Geoipocian Fascist Revolutionaries, Novostia won the war

The war was declared after the December 10th Incident, or the Novisbourg Square Massacre where Darenian funded Militia got past security through Insiders or brides (Or both), 371 People were killed in the incident
Casualties

Military:
Novostia: 3.6 Million
Western Alliance: 11.7 Million

Civilians:
Novostia: 18.2 Million
Western Alliance: 72.3 Million

Total: 106.8 Million

[Syndic Australia]

The largest war our nation has fought occured just before its current iteration, and was a major factor in the change of regime. The Great War, which lasted until 1921, saw over 700k Australians shipped off to war - 14% of the population at the time - of which ~400k enlisted and ~300k were conscripted. About 170k New Zealanders were similarly sent to war, a similar percentage of their population.

The Great War resulted in a bloody stalemate, and was even more devastating than in OTL, triggering many revolutions (including our own) and aftershock conflicts. There were ~96k Australian fatalities, and ~210k casualties (including prisoners of war), as well as ~29k Kiwi deaths and a further ~76k casualties.

Our nation's only territorial gains from the war was that of German New Guinea, and this was a de-facto gain, never formalised by a treaty.

---

Otherwise, our cold war with Indonesia, the Long War, over the disputed islands of New Guinea, has been going since 1931 until the present (2024), though Australia has had relatively few casualties (less than 1000) during those 93 years as a result of the conflict.

[Ermarian]

The most devastating conflict in the history of our world was the Shard War, fought some seven hundred odd years ago between the Empire and the Deep Alliance. It lasted close to eight years and resulted in the deaths of close to eight million sophonts. (At the time, the population of the world was just shy of one billion.)

It ended with an armistice formally signed at the Vahnatai city of Olgai on the third of Evermoon, 1424. Technically a surrender in all but name (as the Alliance had at that point spent virtually all of its industrial power, and was fracturing), it nonetheless resulted in the permanent peace treaty now named the Accords of Olgai. This happened essentially at the insistence of the Imperial Council, overruling the Empress (as well as populist sentiment), who intended to push for a prolonged occupation, and eventual annexation of the defeated belligerents.

The third of Evermoon, the third day of the New Year, remains a national holiday seven centuries and dozens of generations later. Unlike the celebrations immediately preceding it, it is a day of sombre commemoration.

- the Shard Wars, in which the Empire's (and Avernum's) united expansion into the lower caves (especially the Mare Profundis region) kindled a united resistance by the other subterraneous species who feared an incursion into their territory. They struck preemptively and formed the so-called Deep Alliance. The devastation was terrible, and did not remain limited to the caves: The Deep Alliance used powerful weapons to induce seismic events, destroying many surface targets. The Empire won, eventually. This was five centuries ago.

In more recent history, we had Empress Nahema Stark I. (15th century a.i.), under whose expansionist ambitions the Empire attempted to colonize further reaches of the caves. The civilizations that lived below (chiefly the Vahnatai and the Slithzerikai, as well as other, even remoter denizens of the abyss) perceived the threat and formed the Deep Alliance to halt the Empire's intrusion. The Shard War that followed (so named for the devastating use of crystallothaumic weapons of mass destruction, or crystal shards) was deadlier than any conflict in history for raw body count (though not relative to population).
It is estimated that about 800,000 Imperial soldiers and 600,000 Alliance soldiers perished, and more than two million civilians were killed directly; more than three million as a result of famine and disease in the parts of the caverns that were cut off by the war.

[Naxera]

Gònava War 1996-2000. We as country blooded dry at all levels. Manpower, financially and technologically. Fighting for the thinly populated semiarid plateau of Gònava. We tripled our country size. We had to struggle to keep our military operational as We were not a very affluent country.
Our country was then populated by 1.75 million (now. 2.25 million) inhabitants. There were 70000 civilian displaced. Our army increased from a peacetime force of 7500 to a peak of 150000 (Now We have 15000). We suffered 35000 fatalities and 2556 pows and MIA. We in the aftermath, We had lost the about a quarter of our GDP We had a debt of 175% of our GDP.

Indeed We had already fought in the same region in 1974 and 1985 and the fight was short and very vicious involving little forces per side.
Our General Staff had the believe that that if it hadn't been for Covid pandemy and a Catastrophic explosion in a Lololian military depot we would had ourselves engaged in another war.

[South Americanastan]

Americanastanian War of Independence, 1971-1979. We declared our independence from America and Canada. After a large offensive by Canada and our own offensive into the Adirondacks and 3 years of heavy fighting, the front devolved into trench warfare, with helicopter raids being our only saving grace. All land above the St. Lawrence River, (Which is the IC reason we have “south” in our name) but gained the Adirondacks.

Casualties:
Americanastan: 657,000
USA: 523,000
Canada: 678,000

[Alaska Hawaii and the Aleutes]

Probably the Qhayü War of independence or the Qhayü war for sovereignty.

1. The Qhayü War of independence was a war which started in October 1957 and officially ended in January 1959. The Qha declared independence from Britain, France, Canada and the US. With France they settled it quite early with diplomacy which is why France and Alaska kept good relations and the first capital was Noumea. Britain refused at first, but since Vanuatu was a shared colony and France already gave it up, they also left the war. Canada was fighting for the west of their country and the US was fighting for Alaska, Hawaii, Washington, Oregon, Idaho and the overseas territories in the Pacific. In December 1958 when Alaska almost lost, they told the US that they are going to join the Soviet Union if the US doesn't leave the war. The US accepted, but said they's keep Idaho, Oregon, Washington and their military bases. Canada kept fighting, but lost because of population disadvantage.

Casulties
US: 10,000 (low)
Canada: 2,000 (Very high)
Britain: 1 (very low)
Alaska: 11,000 (high)
Treaties
Treaty of Noumea (Alaska, France)
Treaty of Port Vila (Alaska, Britain, France)
Treaty of Point Roberts (US, Alaska)
Treaty of Boundary Island (Canada, Alaska)

2. Qhayü War of Sovereignty

This war started in 1886 and ended in the same year. The participants were Alaska (Back then 'Karale Xayase ы Qha'enya'), Britain, the US, France, Spain and Germany. In 1867 Alaska became its own country in fear of getting claimed by another country. Alaska was recognized by the Russian Empire. The Country was roughly the same size as today. This resulted in Britain not giving Canada the 'Dominion' status and keeping it as an incorporated territory until 1890. The war started as the scramble for Africa ended. Many European powers disliked the existence of a country bigger than Europe itself and that ended in the Qhayü War of Sovereignty or 'the scramble for Alaska'. Alaska was split and Russia managed to take the Western and Northern part of Mainland Alaska, St. Lawrence and the Diomede Islands as a protectorate with Qhayü approval, but the rest wasn't so lucky. Mariana was given to Spain, The New Hebrides were split by Britain and France, Kodiak and Southern Alaska was given to Germany, The Eastern Part of the Country became a part of the British Empire and later, Canada. The rest was handed to the US.

Casulties
Germany: 12
Britain: 789
US: 540
France: 107
Spain: 10
Russia: 0
Alaska: 20,000

[The United States of Nuclear Weapons]

Probably a tie between our Independence War between us and the United States, because of a estimated loss on both sides being 225,000,000-425,000,000 people, and equaling 200 billion dollars of debt worldwide, and our first war with the EU, with fatalities equaling 300,000,000-550,000,000, and being 2.2 trillion dollars of cost worldwide. This is also when the 3rd, 4th, 5th, 6th, 7, and 8th nuclear bombs were dropped, one on us as retaliation from the EU for us launching 3, at which we launched two retaliatory nukes.

[Cavino]

The Great War 1959-1966

-WW1 and WW2 didn’t happen in my universe-

The Great War was a massive global conflict in the 1960’s. The war started because a dictator was elected in the previously democratic country of Saxony. Saxony began to expand and fight with its neighbours, quickly escalating into a continental conflict engulfing Europa. Cavino was safe across the ocean. Saxony began to massacre Jewish people within its borders. The Cavinican government began to panic, but the public still didn’t want to get involved in the war. West of Cavino, sits the country of Osaka. Osaka decided that now was the best time to begin their expansion as well. One of their goals being to control the west coast of the continent of North Cavino. The first thing they did was a bombing raid of the city of Porta Plata, Catalina, USC. By bombing Cavino, they’d poked a sleeping bear. Cavino unleashed its industrial and military might on Osaka. Osaka was getting desperate, but they refused to surrender. Cavino began developing many different technologies. Including the atom bomb. In 1966, they dropped the first atom bomb on an Osakan city. They dropped two more atom bombs on two more cities before Osaka surrendered. In Europa the war was won by more conventional means. The Osakans surrdeered on July 18th 1966, the Saxons on August 1st.

Technological Leap Forward Because of the War
1959-1975 was the largest technological leap in human history. Before the war most Cavinicans lived in log cabins and rode horses or very primitive cars. Most homes didn’t have a telephone, radio was just becoming popular. Televisions had just been invented in 1956. In the 1970’s all of that changed. Most Cavinicans came into a lot of money and nice houses with electricity and telephones began sprinting up nationwide. Fashion changed to reflect the new excess. Televisions which were in 0.1% of homes in 1959, were in 45% of homes in 1980 and 95% of homes by 2020. Cars began to get BIG. Both physically and in popularity. Horses were almost completely gone by 1975. The first mass market robots and computers became available in the 1990’s, after on the world’s first computers was used to crack Saxon code during the war in 1964. With all this new technology and excess came the new fear, the atom bomb.

The War Still Affects Us Today, 55 years later.

In the center of the nation’s capital city, Lawrence, stands the tallest structure in the city. The Freedom tower is a memorial to the Great War and the freedom protected and restored by our brave men of the military. In the outskirts of the city, is Dorchester National Cemetery, where 300,000 crosses stick up from the ground, surrounding a beautiful oasis of trees.450,000 Cavinicans were killed in the war. 70 million were killed in total. Many veterans of the war are still alive today, in their early to mid 70’s.

[Dusendord]

War of Olollipop

[Wochaystein]

The Trouble across the Four Corners is a major civil war between the supporters of the major sibling-claimants to the title of Emperor: Adalbert, Adaldunk, Grimbert, and Grimdunk. It was never resolved and caused the shattering of the Holy Empire. All of its successor states claim that they are the "true" Empire.

[The Union of British North America]

The War of Wars, aka the Great Global War or the Great War or the World War, was the largest conflict in human history, taking place from 1936 to 1943. The Two-Ocean Entente of the United British Commonwealth of Nations/British Empire (led by the Anglo-American dyad of Britain and the North American Union), France, and China against the Germans, Polish, and Russians with their Middle Europe/Russo-German Alliance. The war's main fronts were the West European Front, Balkan Front, Mongolian Front, and the South African Front. All oceans were also sites of submersible and surface ship combat. Japan was a co-belligerent of the Two-Ocean Entente, and by secret negotiations with the Western Entente were allowed to occupy many German Pacific and Asian colonies.

75 million people, military and civilian, were killed or wounded, 12 million displaced, and 5 million globally died from the influenza pandemic that came after the war. The genocide of 1 million Africans and United Commonwealth prisoners of war who were non-white by the rogue German Field Marshal Josef Eichler in South Africa and in German Central Africa (aka the Congo) were also among the dead of a terrible, needless war. But the war catapulted China, Japan, and the NAU to great power status.

[United Kingdom of British Isles]

The Great war aka World war Emu II.
23 million brave soldiers died in our struggle for freedom against the emus.

[Crabaiaia]

Savia War.

The 2nd Beta Uprising leads to a war in a city not related to inceldom

[Johto-]

The largest war the modern FRJ has been involved in was the Great War, which took place between 1977 and 1985. It was the deadliest war in modern history and the second deadliest war in recorded history, killing approximately 128 million people and over 14 million Pokémon. It also known as the "War to End War", as no major wars have ever been fought in the nearly 4 decades since the War's end.

The war began with the Second Orreian Empire's invasion of Johto. Orre was aided by its allies allies - the Almian Federal Republic, the Pasian Monarchy, and the Sevii Republic - while Johto was aided by Kantonese Empire, the State of Sinnoh, the Third Hoenni Confederacy, and the United Unovan States. The Galarish United Kingdom would soon join Orre and Oblivia would aid Johto after being invaded by the Sevii Republic.

The war ended with extremely controversial use of the Pokémon Ho-Oh by Johto. The Pokémon rampaged across Orre and especially Galar until it was eventually calmed down by Lance Steelwing, the 127th Champion of Johto.

[Savroyska]

Quite obviously World War III, a conflict spanning from 1992 to around 1997 and causing the deaths of millions worldwide. In one universe (The Post-War Universe) it led to a thermonuclear war killing billions and officially putting an end to pre-war civilization for centuries. In another, 460 million people died and thermonuclear war was limited but Berlin, Dresden, Leipzig and Munich were nuked by the Archangel Pact while Paris, Kiev, Nizhny Novgorod and Volgograd were nuked by the Leipzig Sphere. On other continents, Birmingham, Buenos Aires, Curitiba, Recife, Pretoria, Kinshasa, Delhi, Mumbai, Calcutta, Beijing, Shanghai, Tokyo, Nagasaki, and Jakarta were all nuked by either the Leipzig Sphere or Archangel Pact. The recovery process is still ongoing and will likely finish by the 2010s.
In a top 5 list:
1. WORLD WAR III; 80 million dead (39 million in nukes, 41 million in combat both military and civilian)
2. WORLD WAR II; 7 million dead
3. WORLD WAR I; 2.6 million dead
4. THIRTY YEARS WAR; 2.2 million dead
5. NAPOLEONIC WARS; 2.1 million dead

It is currently 2000 in the Pre-War timeline and the war-shaken nations of the World are about to get struck with something...something that could be worse...