Condition Harbinger is a strong Torment-based DPS build.
Unlike Death Shroud, Harbinger Shroud does not protect the Harbinger’s health pool while it is active. Harbinger benefits from self-inflicted Blight stacks by utilizing Shroud skills that consume Blight in exchange for more damage.
Make sure to transfer the self-inflicted conditions from Blood Is Power by using Deathly Swarm. Be quick, or else your teammates will cleanse your conditions before you can transfer them to the enemy. If necessary, move out of the group to avoid being cleansed.
Always use Elixir of Ambition while above 10 stacks of Blight, as this doubles the duration of the conditions it applies to enemies! Generally, Harbinger Shroud and your basic Elixirs generate enough Blight that meeting this threshold isn’t an issue, but be careful during your opener and any phase transitions.
Elixir of Ambition gives you every boon in the game, including Stability, Aegis, and Resistance. While it’s never worth it to delay this skill just for this, sometimes it will line up nicely with a mechanic and allow you to block or ignore an important attack.