Path of Building: https://pastebin.com/hm4rkxFM

6 Power Charges, 6 Curses, 99% reduced duration Impending Doom

Using several uniques and the Window of Opportunity wheel, this buid achieves 99% reduced duration of temporal chains to allow for very rapid proccing of Doom Blast. This build uses power charge stacking to achieve a curse limit of 6 while maintaining a high critical strike chance. This allows the use of powerful offensive and defensive curses to scale the damage along with the Occultist Ascendancy. Sanctum uniques are used to scale cooldown recovery rate and get elemental damage reduction.

Full build guide including mechanics and gear suggestions in the linked forum post.