Progression is simple:
Start with [Physique] in your Aura slot.
Add Polarities for [Blind Rage], [Venom Dose], [Augur Reach], then [Cunning Drift]. In that order.
Keep Umbral mods on as much as possible.
Finally add the Aura polarity to swap to [Corrosive Projection].
This thing is a god in [Sanctuary] Onslaught, so do your leveling in there. You can have this build done in a few hours of grinding because its so easy to rank up.
If you are having issues with Energy swap [Augur Reach] for Streamline, or Fleeting Expertise.
If you are having issues with survivability swap Venom Dose for Regenerative Molt.
Comments/Suggestions?