The Pandemonius is acquired only from using the blessing on The Halcyon. The roll of the original item is not carried over to the upgraded item. The description of the The Breach divination card suggests it can rewards any unique Breach item, however it is not confirmed that it can grant Blessed unique item or not.
+(20-30) to Dexterity
(20-30)% increased Cold Damage
+(35-40)% to Cold Resistance
Chill Enemy for 1 second when Hit, reducing their Action Speed by 30%
Blind Chilled Enemies on Hit
Damage Penetrates 20% Cold Resistance against Chilled Enemies
A single moment sets in motion an eternal fall,beneath which all are buried.
A simple tool to price check your items in path of exile by "copy and paste". It is that simple!
Price in Leagues