The Ethnostate Wars (non-narrative)
During the Age of Exploration the races of humans, dragons, and orks all began space exploration in early generation ships. They formed empires as large as could be maintained with the travel methods available at the time, which was not especially large. This resulted in patchworks of small polities forming as ships slowly crawled through the local volume.
As laser canal construction became more common the rapid expansion of territory became possible and the size of a feasible empire increased. Empires on the edges of explored space were much larger than their older neighbors and were more prone to territorial disputes as a result of rapid exploration and colonization. Even at the new size that nations were achieving all races were still only collections of various vaguely aligned states and polities and so conflicts were generally small in scale. When larger conflicts did occur it was not over individual disks or stars, but over the infrastructure of existing laser canals which an empire could redeploy elsewhere to leave their neighbors weak and allow for existing infrastructure within a polity to be expanded and increased in capacity. With the technology of the time it was generally easier to expand the capacity of shipping lanes within close systems than it was to acquire new systems outside of reasonable transport time.
As the local volume of systems were colonized and less and less space was available to expand into border disputes became much more common. No longer could a fledgling empire hiding in a remote sector of space and operating without a laser canal avoid the hungry eyes of their neighbors. So in order to strengthen themselves against conquest many nations created treaties amongst neighboring nations with whom they had racial commonality and over time several major powers emerged within each race's respective volumes. The wars between these major but not yet fully united empires are known as The Ethnostate Wars and the horrors of those wars form some of the most impactful events in history.
The human and orken empires both independently developed liquid salt nuclear furnaces that powered their void ships and served as ritual components and power sources for summoning their gods into the material realm. This is a terrible idea that will have significant consequences for everyone. Once their gods were summoned they were suited in massive power armor as tall as a disk is wide. These terrible titans of war enabled the final ethnostate war to reach apocalyptic proportions. Combatants died in the trillions on nearly every disk the armies of any ethnostate came near, with void war enabling entire planets to be cracked and stars to be snuffed out. The wars even spilled out into the realms above and below, with much of the rivers of those realms flowing with more blood than water.
The Ethnostate Wars came to an end when the human god of war and the orken god killed each other simultaneously in battle towards the center of the bi-frost network. With their deaths the two races quickly lost their taste for war. This coincided with a series of kobold rebellions that had caused the draconic empires to largely abandon offensive actions as forces had to be devoted to internal strife instead. Whether the zeitgeists of the human and orken races had already tired of war when their respective gods were slain or whether their deaths caused the change in the zeitgeists is unknown and is a matter of considerable debate even to this day.
Following the death of their war god a new god ascended to that position and made the decision to not respond to summoning rituals any more. The largest orken empire and a few client states began The 3rd Orken Holy War inm an attempt to kill this new god and replace them with yet another war god but this time one who could be summoned. The 3rd Orken Holy War was successful in killing the existing god of war but when the new god ascended they too refused to manifest in the material realm. The new orken god of war was not alone in this refusal as following the end of the ethnostate wars no gods of any realm are willing to manifest for any reason.