Hexblast will deal 100% more damage as well as AOE damage when it can remove a curse with the lowest duration, this can be problematic when you self cast curses as you will eventually run out of curses on the monster. To get around this we use Elemental Weakness in a blasphemy set up and Temp Chains on hit to bounce between these two when Unleashing on the monster.

Curses linked with Blasphemy have no duration and Temp Chains has the lowest duration at lvl 1 of all curses. This means we can constantly cast Hexblast with no fear of Frostbite being removed until the duration remaining dips below the Temp Chains lvl 1 duration which is 6.6 seconds.

We have Assassins Mark and Frostbite in a Vixen's Entrapment gloves so that when we self cast Temp Chains it applies all 3 casted curses at once on the mob. Unleash then follows the below order:

1. Remove Ele Weakness (Apply Temp Chains on hit, apply Ele Weakness from Blasphemy)
2. Remove Temp Chains (Apply Temp Chains on hit)
3. Remove Ele Weakness (Apply Temp Chains on hit, apply Ele Weakness from Blasphemy)
4. Remove Temp Chain (Apply Temp Chains on hit)
5. Remove Ele Weakness (Apply Temp Chains on hit)

The reason we need Temp Chain on hit for gloves (or Enfeeble) is because the server tick is slower than the reapplication time for Ele Weakness in Blasphemy, Hexblast always needs something to remove to deal big damage.

It bounces back and forth like this until Frostbite goes below 6.6 seconds at which point frostbite will be removed and you should cast the original Temp Chains again to proc Vixen's Entrapment which refreshes Frostbite duration.

Assassins mark will not be removed by Hexblast as it has infinite duration, if it is the only hex on the mob it will not deal more damage or AOE damage.
POB: https://pastebin.com/823Ksptw
Edit: if anyone has some ideas about pushing more damage without sacrificing defences I'd be very interested, I've POBd an EE variant but the damage was the same with Mastermind of Discord.