Started with Victoria 2 in 1836, and in 1936 converted the save to Hearts of Iron.
The Austrian Empire emerged from the peace following the Napoleonic Wars as a cornerstone of conservative monarchism in Europe.
However, the rising power Prussia threatened to destabilize Europe with its aspirations on the German Confederation. After a series of knock-down wars, Austria cemented itself as the pre-eminent German state, and unified the North Germans and South Germans into one German Empire. The Hungarians, the second-largest ethno-national group, proved not to be a problem when nationalist stirrings remained dormant and easily placated.
After the founding of the Empire, various powers, envious of the new united Germany fashioned an alliance as a counterweight.
France and Russia in particular suffered resounding defeats, were stripped of border territories and their pride.
Germany, having missed out on the Great Game to colonize Africa and Asia, contented itself with taking over the administration of Dutch colonies as it integrated the West Germans into the united German Empire.
Soon, countless North and South Germans joined the Dutch and Boer immigrants in South Africa.
Thanks to a new vast colonial empire and a strong economic heartland, the industrial revolution brought unprecedented riches and opportunities to people all over the Empire.
However, new developments also lead to new ideologies. In particular, Liberals and Socialists. Liberals wished to create a completely free capitalist society. Socialists wished to be rid of the capitalist and noble upper classes to protect the workers.
These movements gained great traction in Germany, and the rest of Europe. Germany handled the new ideological shift the most successfully, as it passed economic reforms to appease the socialists, and political reforms to appease the liberals.
Soon, the monarchy was a democratic constitutional monarchy, guaranteeing the best public welfare and education for the masses. Violence had been avoided through compromise, and citizens of the Empire were all better off for it.
Other countries did less well.
In Britain and France, the constitutional monarchies allowed liberalization, but did not protect their workers, resulting in massive socialist upheaval. Furthermore, Communist insurrections tore down their colonial empires.
New Zealand, Canada, and India broke away from London, and French Africa from Paris.
Algeria was nearly lost as well, but luckily the Algerians were divided with in-fighting between Socialist Berbers, and Islamist Pan-Arabists. France was able to reassert control after years of local devolution which saw expanded citizen rights for the locals to better integrate them with the European settlers.
Russia suffered from disastrous rebellions which climaxed with a temporary communist takeover, the destruction of the royal family, and descent into civil war, which was won by the Anarcho-Capitalists bourgeois dictatorship.
Now that Germany was guiding Europe into a new era of Democracy, it was hoped that peace would return. However, in 1937, France and Britain attempted to invade Germany. With this final victory, Germany was able to defeat France once and for all, securing mainland Europe under one unified system. The small prince Henri VII was made to kneel before Otto von Habsburg.
France-in-exile, its monarch and homeland captured, was re-invented as a North African republic.
The war for Europe was over. The War for the World, was about to begin. The spark was lit in China. The Qing dynasty had reigned for centuries, but the Chinese Empire was growing weak compared to the Europeans, who forced China into unequal treaties. The rising Japanese Empire backed up local rebellions, and the southern provinces became independent. Russia had also captured Mongolia and the Manchurian homeland of the Emperor.
China sought to rectify their situation and went to war with the Japanese-Persian-Southern alliance. However, the Chinese Empire committed atrocities against the Europeans living in the concession cities along the Chinese coast, and all Western Great Powers declared war on China.
The War became truly global when Latin American border disputes became entangled with the Chinese-Western war. Fascist Peru attempted to recover stolen land from their neighbors. Haiti invaded the Dominican Republic. The Ottoman Empire invaded Yemen and Egypt. India invaded the disputed Kashmir region. All new aggressors were defeated and completely occupied.
Not wanting to miss out on destroying despotism, Germany began a surprise invasion of Russia, quickly and decisively liberating it for Democracy.
At last, only China continued to struggle. Against the might of the world united they raged, and countless millions paid with their lives, but it was not enough.
After the destruction and horrors of the World War, peace is restored, but the world remains divided between nations and ideologies.
Note: Even with a POD in 1836 instead of 1936, Italy is still fascist and a stupidly incompetent ally for Germany. I don't know why I didn't just invade them