The Blade of Eternal Darkness has no specific class restriction, it is aimed more towards mages, warlocks, and to a lesser extent, priests. If a character wields this dagger and casts a damaging spell on an enemy, there is a chance that the dagger will deal 100 Shadow damage to the target as well as restoring 100 mana to the wielder.
Source
The blade drops from Princess Theradras in Maraudon.
Notes
The blade's drop rate is estimated at 0.1%.
The dagger was changed in Patch 1.10. Previously, the proc was an "On Use" ability with a 1.5 second casts and a 30 second cooldown.
External Links