Power Scourge
A power Scourge for the zerg backline — shades put damage, 
Barrier and boon corruption on the fight without you walking into it.
Read the trait line honestly: two of its three Scourge majors are barrier traits. This is a support that carries a Greatsword, not a damage build that happens to shield people.
Why these traits
Desert Empowerment makes 
Manifest Sand Shade shield everyone standing near it and hands boons to whoever you shield; 
Abrasive Grit then makes that same Barrier cleanse conditions and grant might. 
Feed from Corruption closes the loop — every boon you remove or corrupt comes back to you as Barrier, and this bar corrupts constantly through 
Well of Corruption, 
Trail of Anguish, 
Ghastly Breach and 
Nightfall. 
Blood as Sand is always on and quietly matters: you take less damage from everything while a shade is up. Spite and Soul Reaping supply the power scaling underneath.
Gear reasoning
Marauder and Assassin's under 
Scholar — precision-heavy with enough vitality from Marauder to eat a stray bomb, because your damage arrives as a lot of small shade ticks rather than one Greatsword swing. 
Nullification and 
Absorption are more strip, and 
Garish Pillar is the fear that sets up Absorption's interrupt. 
Energy refunds endurance on swap, 
Bloodlust stacks power. 
Cerus fires off your elite, so Ghastly Breach also summons an eye that converts boons into conditions — the whole set is pointed at the same thing.
When not to run it
Scourge does not push, it holds. If your squad is the one being pushed onto, this is its fight; if you are the hammer, take Reaper.
One more thing to know before you pick it: your Barrier income runs through Feed from Corruption, so it depends on there being boons to strip. Against a group that arrives with nothing on it, you shield far less than you think.