What about Mongolia then? (ideally Kaiserreich... Ungern-Sternberg!)
Alright, after a long long break I'm getting back into mods, starting with KR.
I think I might do one or two more of TNO. I think I'll focus on USA and then maybe I'll think about a russia-centric one, since that by far got the most votes.
And back to your regularly scheduled programming:
Ungern-Sternberg seized absolute control over Mongolia. Having sidelined the monarchy, he set out to crush the western rebels. After a short military buildup, Mongolia swiftly invaded the San Ma, liberating territory inhabited my ethnic mongols, which greatly expanded the ability of the Mongol state to recruit manpower for the still undersized army, compared to the other chinese factions.
The cavalry tactics that Mongolia used consisted of delaying pinning attacks from some divisions, while the others exploited breakthroughs in the lines to rush forward deep into enemy territory. Being able to live off the land gave mongol divisions no supply lines to worry about, so their movement speed and resistance to attrition were superb. By operationally outmaneuvering the slow chinese infantry, Mongolia quickly conquered all of San Ma.
Next on the menu was Sinkiang, which had just been conquered by the Kumul Khanate. They also attempted a cavalry-mobile style of warfare, but having themselves just come out of war, they were less well equipped and overrun by superior Mongol numbers.
Having acquired new territories, population, and industry, Mongolia set out to expand the army further, reaching the size of two army corps, requiring two generals to manage, with Generalissimo Unger-Sternberg himself serving as supreme commander in the field.
The economy was improving radically despite the betrayal of Russia, who pulled out investment to focus on their domestic issues in Western Russia, where the risk of syndicalist revolution was brewing.
Meanwhile, Chinese warlords had mostly united under the leadership of a Left-wing KMT, which after defeating the Beijing garrison, began to fight with the Manchurian Fengtian group, the last large group that hadn't unified with the southern government.
Mongolia planned on exploiting Manchuria's war with the southerners in order to easily invade.
However, just as the divisions had positioned themselves on the Manchu border, Russia declared war! It was a total surprise and the army was completely out of position, having committed to attacking in the East, instead of the North and West.
So quickly, the army repositioned to face the Russians. Luckily Mongolia was saved by Russian incompetence, as despite having an army that outnumbered Mongolia 4 to 1, the Russians had failed to communicate their orders and plans, thus the Russian siberian divisions was also far from the border and not ready for a coordinated attack.
Mongolia's units repositioned quicker than the Russians and launched an immediate counter-attack, capturing key junctions of the trans-siberian railway. Despite being heavily outnumbered, the Mongols used their cavalry to speed around the Russians, creating pockets of soldiers who easily surrendered. By repeating the cycle of breakthrough-encircle-liquidate, Mongolia destroyed most of the Russian army by the time they finished crossing Central Asia.
Crossing the Urals was less of an epic struggle, and more of an impatient jog across the the Russian landscape on the way to Moscow and Petrograd, which finally caused the Russians to surrender. Ungern-Sternberg did not trust the failed Russian leaders with any level of self-government and instead chose to fully integrate Russia into the New Mongol Empire.
Also, Ungern-Sternberg had initially been highly statocratic in his worldview, but with the needs of war and building up the Mongol army and state, very meritocratic methods were used, and radical ethnic equality measures were enacted in order to convince the majority non-Mongol population to accept their place in a Mongol empire.
The army swung back east across the Urals and Siberia to finish off Manchuria, though Beijing fell back into the hands of the KMT. With the surrender of the Manchus, Mongol divisions simply starting recruiting them and kept marching, this time blasting their way across Chinese divisions, who melted under the unexpectedly high fire concentrations that the Mongol army produced.
All looked to be going smoothly, then the Mongols captured Nanjing, it should have been a moment of crowning triumph but instead marked a new dangerous turn: Foreign Intervention.
Japan, growing jealous over the Mongol takeover of China despite their own failure to usurp control of the Legation Cities, lead to Japan declaring war on Mongolia.
Mongolia, using some captured Russian naval vessels, was able to park a small fleet right at the tartar strait that separated Sakhalin island from the mainland. However, the Mongols could not challenge the naval superiority of Japan anywhere else, so after overrunning Sakhalin and Korea, most of the Mongol army would be relegated to passive coastal garrison duty to prevent Japanese amphibious landings.
The rest of the Mongol army kept moving south, into Tibet, Siam, and Indochina. The Mongol overspill of the Siam war into Vietnam prompted Germany and its Reichspakt to declare war on Mongolia, especially since Mongolia was threatening to seize the Chinese port cities.
However, again the declaration of war took Mongolia by surprise and there was a great rush for the Mongol divisions to take the long train ride to Moscow before Baltic divisions could overrun too much of Russia.
As for the state of the rest of the world, the Entente had already long been at war with the Internationale, mostly fighting over Latin America, since French Africa was liberated too soon for Entente intervention. Then, trouble in Switzerland, Italy, and Belgium resulting the Internationale also being at war with the Reichspakt. The Internationale was stymied in Trench Warfare in Europe, but was able to save most of the rest of Africa was Goering's horrifying excesses.
Mongolia swiftly defeated the Germans and their allies in the East, and to secure their flanks, destroyed the rotting Austrian Empire once and for all. The Hungarians, grateful for their liberation, joined the Mongols and as a reward for their great cooperation were allowed a semi-independent buffer state to separate the Mongol Empire from the Internationale. The same was done in the south with the Bulgarians.
Having successfully combined Russia and China into a new super-empire, and defended it on all fronts from several great powers, Mongolia had a free hand to use its now enormous army to subdue the rest of Asia. This would put Mongolia into conflict with the Entente, which was still protecting India, which meant that despite their great differences in social outlook, the Internationale and Mongolia were strategic partners and would stay peaceful with each other.
The Entente failed to liberate Central America and Indonesia, but manage to hold on to Cuba and Venezuela, despite the Entente's naval blockades.
Japan, having lost all mainland holdings and even being forced to give back Hawaii to the USA, is now part of the Entente.
The USA avoided a syndicalist civil war by promising social democratic reforms to the economy, but then had to fight a civil war against the South under Huey Long anyway and ended up reneging on the deal, instead becoming Liberal like Canada. The USA is not yet officially part of the Entente, but is very much aligned with them and provides substantial support to global effort against the syndicalists. With hostilities settling into a simmer now that major land warfare has ended, the USA will be more free to openly join the Western side of the Cold War against Europe.
Mongolia, being anti-democratic and anti-socialist endeavors to simply exist as a neutral bloc that happens to be sitting on most of Humanity while the peripheral nations around the World Island continue their pointless conflict.