The Black Rain

The Black Rain, also known as March Madness, Dyrrn's Invasion, or simply The Corruption, refers to a series of events where Dyrrn the Corruptor tried to invade Eberron's surface from his prison in the Khyber. Several cults dedicated to Dyrrn and the other Daelkyr managed to corrupt various lands throughout Eberron to prepare for Dyrrn's arrival. Four guilds, Ranger Corps, Magical Girls, The University, and Red Dragon Free Riders, separately dealt with the cultist activity in each land to prevent Dyrrn from being unstoppable if he successfully escaped his prison.

These events culminated in a showdown at the highest point in Sharn, where Dyrrn physically manifested himself along with other eldritch abominations he had created. The prelude to his invasion was a torrent of the eponymous black rain that corrupted any who touched it. Dyrrn was defeated by a group of adventurers and the leaders of the guilds involved by using a Soul Forge to imprison him inside of a body and then destroying it. The guild leaders were all prepared to be the one to die, but ultimately it was Rex Cassidy of the Red Dragon Free Riders who sacrificed himself to save Eberron.