Black Dawn

The Black Dawn is the unofficial but the widely accepted name for a crime against humanity the likes of which hasn't been seen in the Aegian system or any inhabited star system within 100 light years of the planet Corsair. Perpetrated by the Blood Knights, the purpose of the Black Dawn crisis was to break the back of the Corsari government, military, the people and the planet as whole. The Black Dawn even was planned for years prior to it being carried out by Crimson, the commander of the Blood Knights and was the ultimate goal of the Blood Knights from the start; all of this unbeknownst to the greater Dread Empire.
The Black Dawn crises was meant to bring about Armageddon on Corsair with the intent to kill as many people as humanly possible. The death toll was of apocalyptic proportions with estimates stating as many as 176 Million people died in the Black Dawn event. Black Dawn was carried out by detonating 15 multi-megaton nuclear devices in 15 of the most populated cities on Corsair, which resulted in the destruction of critical science, culture and military infrastructure. Several Corsari scientific and weapons programs were set back years due to this event as well culture as a large number of actors, musicians, play-writes and other cultural industries were decimated in the strikes.
The Black Dawn catastrophe was a well coordinated event as all 15 weapons were detonated within a span of 3 minutes giving the Corsari and Dragonian High Command enough time to individually process each strike before the next one hit. The intent here was to have a compounding demoralization effect as the gravity of each explosion would add more and more pain to each subsequent one. Luckily the Corsari capital and the Kessad province as a whole were spared from the initial blasts. Kessad however, nor the rest of the planet, were spared from the fallout, global climate changes, and massive waves of refugees that resulted from the strikes.
Despite all the deaths and destruction, which should've sapped any will to fight from the Corsari forces, it backfired majorly. While the act was universally abhorrent, it caused a massive paradigm shift for everyone involved in the conflict, military and civilian alike. The primary result of the destruction was the everyone turned against the Dread Empire in almost an instant. The Dread Empire itself was furious with the Blood Knights and Crimson as that one act completely undone everything that the Dread Empire was fighting for. Their support for the war from the people dropped to nigh zero almost overnight with that act. 
This caused a massive defection in the ranks of the Dread Empire with the Saelan Corps and the Constantine Tank Brigade breaking off from the Dread Empire and actually becoming openly hostile against the Dread Empire and Blood Knights, declaring war on them and striking at the heart of the Dread Empire as that's where the Saelan Corps was stationed. This allowed the Saelan Corps commander, Admiral Hayden Allderdice, to launch a massive coup attempt against NeoCrimson. The provinces that made up the Dread Empire fractured and the Empire splintered into multiple factions that no longer answered to a centralized leadership as the individual Admiral Caste that made up the Dread Empire leadership returned to their respective territories to build up the forces under their command for the coming onslaught by the Dragon Alliance.
With how destructive this event was, it's hard to believe that it was actually meant to be much worse. When the AcDragonian forces assaulted and ultimate seized control of the Gal Da Val islands in the Straeslach Sea they uncovered the existence of an immense Supernova Core that wasn't ready to be used. It was much larger than anything the Corsari government dared to create. The estimated blast yield of the weapon, if detonated, was speculated to be in the range of 62 Exatons. The largest the Corsari military has in their possession and that has ever been created up until that point is 4 Exatons. Physicists almost universally agree, even without ever having a scientific projection to go off of that this weapon would've cracked the planet in half and if the planet somehow miraculously survived the blast there would be a crater most likely reaching the core of the planet. The planet would be rendered uninhabitable and all life on the planet would die either instantly or very quickly after detonate as the atmosphere would be burned away. While originally the assault was to seize control of the Ion Cannon, the discovery of the Supernova Core prompted an investigation into where exactly the Blood Knights got the funds to purchase and for the matter, the source of their Caramine mineral which yielded some shocking and frankly, unbelievable results.
The Black Dawn crisis ushered in the end of the Corsari Conflict.