Storm of the Emperor's Wrath
The Storm of the Emperor's Wrath is a warp storm which appeared in M36, during the Age of Apostasy, soon after Sebastian Thor openly rebelled against Vandire. The storm's strength and persistence is such that, millennia later, it still rages, to this day enveloping the Clax system and isolating it from the rest of the Imperium.
To crush Thor and his rebellion, Vandire sent a great Imperial Naval fleet, carrying the armies of the Frateris Templar. As the fleet attempted to cross through warp space to Dimmamar, the storm engulfed the region, destroying the entire fleet. The storm was considered the Emperor's will incarnate, a sign taken by Thor that Vandire had to be overthrown and the Imperium reorganized.
This term may also refer to the default psychic power used by Space Marine Librarians as an offensive weapon.