Nightfall is a passive warlock ability learned at level 54 for those with the Affliction specialization. It gives [Corruption] a small chance to restore a Soul Shard.
Nightfall can dramatically increase the warlock's damage output.
Nightfall has a 5% chance to proc every time Corruption ticks damage on an enemy target. Corruption ticks every 2 seconds, but can be placed on multiple targets to greatly increase proc chance.
Multiple procs of Nightfall do not stack. The warlock can only have one Shadow Trance buff at a time. It can, however, proc multiple times from the same Corruption spell.
Patch 1.3.0 (07-Mar-2005): Fixed a bug where the Shadow Trance effect was lost without benefit. Previously, the talent had a 3%/4% chance of triggering. It now has a 2%/4% chance of triggering, and the tooltips have been updated to accurately reflect this change. The Shadow Trance buff granted by the Nightfall talent will no longer be used up by a shadowbolt that was in mid-cast.