The Darkening
The Darkening was the result of a combined virtual/realspace terrorist attack against the infrastructure of Aldaain by radical anti-collectivist rebels during the Hemmoian Civil War. Carried out with EMP bombs and a highly contagious computer virus, the attack overloaded The One and Prime PWN causing subspace communications relays to fail, resulting in a cascading ripple effect all over the Collective.
Background
In 3,177 the Hemmoian Civil War reached its final stage when a radical faction within the Rebellion, exhausted by the brutality and pointlessness of the war, launched an unauthorized strike of their own against Aldaain, the command world of the Hemmoian Federation. The radicals hoped to send a message to the Federation, possibly causing them to reconsider further attacks and to turn the tide of the war. Before this, the Rebellion had not attacked civilian targets, but this time a large number of civilian casualties were to be expected.
Execution
The plan was finally put in motion in secret from Karellen and Rashaverak, the leaders of the Rebellion. Using a battle group of Ksamak class dreadnoughts, the radical faction managed to momentarily disable Aldaain's security systems and drop high-intensity EMP bombs and plasmic charges to the surface. A fractal cryptographic parallel processing virus was simultaneously released into The One And Prime PWN, scrambling the monstrous planetary data network for weeks. Vast infrastructural collapses, civilian deaths and the complete collapse of Aldaain's subspace communications, felt throughout the Collective and referred to as "the Darkening", were the result.
Political consequences
The act of terrorism displayed the true potential of the Rebellion for causing catastrophic damage to the heavily Collective-based infrastructure of the Federation. Initially the Great Council was furious and plans for substantial counter-attacks were once again prepared, but as reports of the damages kept coming in the full extent of the Rebellion's knowledge of the Collective became apparent. The Great Council realized further retalitory strikes would simply result in even greater damage to the Collective, causing further defections and chaos and - quite possibly - the destabilization and eventual overthrow of the government. The prospect of losing power over the Collective was too much to bear for the Council.
When the leaders of the Rebellion heard of the terrorism carried out in their name they were initially horrified, but also recognized the fact the radicals had been successful. Realizing the time was right, a cease-fire offer and a possible draft for a non-aggression treaty were immediately transmitted to the Federation by the rebels. The Great Council grudgingly accepted the proposal and a ceasefire went into effect in late 3,177. In the coming rotations remaining IHSF blockade fleets were called off, signaling a de facto recognition of the rebellion's legitimacy. The Great Council assumed a line of concessions, according to their rhetoric hyperbole, "in the name of peace in the galaxy and the well-being of all our peoples," although it was little more than a form of political damage control. The Hemmoian Civil war was effectively over, allowing the foundation of the Democratic Hemmoian Republic.