The Dissension Crisis was a significant catastrophic event that occurred on 31 Cizarm, 10012 ZC. It is considered the culmination of events set in motion during the Decamillennial twelve years prior, as well as the point where the waning power of the Guildpact was finally destroyed. Several factors contributed to the crisis, but chief among them was the rise of the nephilim, the return of the damaged Boros skyship Parhelion from her long absence in Agyrem, and the revelation of several conspiracies by certain guilds for control of Ravnica – several of which were either utterly devastated or weakened in the aftermath.
The most apparent crisis seen by the public were five rampaging nephilim, bizarre creatures of unknown origin that have been noted in Ravnica’s lore for centuries. The five emerged from the ruins of the Cauldron, eventually making their way across the Utvara Reclamation Zone and into the Tenth District, leaving a trail of ruins and death in their wake. All of them were eventually slain, two notably felled by Niv-Mizzet and another by Rakdos, but not before they had caused incalculable damage. What provoked the nephilim is to this day unknown, and no nephilim seen since have yet compared to the power, ferocity and sheer size of these entities.
At the same time, the Parhelion emerged from the Schism that hung in the skies over Utvara, badly damaged and with her entire crew of angels dead, killed in Agyrem by the forces of Szadek. Uncontrolled, the ship flew a straight course and eventually crashed into the spires of Prahv. Both were eventually obliterated in an explosion caused by overcharge in the ship’s mana engines. Whether this coinciding with the nephilim attack was an incredible coincidence or part of some bigger plan is largely unknown.
What did come to light in the aftermath was the actions taken by various guild leaders during the crisis. It was revealed that several were working in conjunction to conquer Ravnica, including Momir Vig of the Simic, the Azorius Grand Arbiter Augustin IV, the Golgari parun Svogthir, and Szadek. Experiment Kraj would be released on the city by Vig, the creature eventually running rampant after Vig was killed and being felled by Rakdos (though not before rendering the demon lord comatose). Augustin would likewise meet a gruesome end, his plan to remake Ravnica under Azorius martial law ruined by the actions of Agrus Kos and his allies, and his soul consumed by Szadek’s wrathful ghost.
While the event only lasted a day, the repercussions of the Dissension Crisis continue to be felt to this day. It revealed the guilds and their weakest as well as the true agenda of some, and the trust of the populace was irreparably broken – speculation holds that the first vestiges of the Gateless Movement started in the immediate aftermath of the crisis.