Zappy Toughness Generator
 Skitarii Build - Warhammer 40k: Darktide 

Taking Toughness Regeneration Speed is not a typical thing to do, but Resurgence exists to make it work when enemies are too close. Combined with Power Overflow, you bleed out toughness to your squishier allies.
 Your sources of toughness regeneration are:

• As mentioned, being in coherency, Resurgence will make it still work even when you're considered "threatened" at half-efficiency.
• Auto-Repair Doctrines just by existing. You get more passive regeneration with more capacitance which Redline Capacitors gives you two more extra stacks.
• Binary Ballistics Protocol whenever you kill elites.
• Power Redistribution Uplink when you land a critical hit.
• Entropic Transfer when you electrocute someone, which is like 90% of this setup.
• Voltaic Overcharge upon using your ability, even better the more surrounded you are. Surge-Extension will also trigger at the same time since you use capacitance. Noospheric Command will also trigger Surge-Extension.  
• Finally, Data Sensor Protocol is your other passive toughness regeneration, which is a shared cooldown with your allies.

The biggest enabler of this build is System Shock. Combined with the Munitorum Mk III Shock Maul's special action for elites in small numbers and Voltaic Emitter for elites in high numbers, you can fight groups of Crushers or Ragers just fine. Pull out the Branx Mk IV Arc Rifle when mob density is too much for your shock maul, and when you're out of/low on ammo just swap back to melee and let Gunsmith refill your rifle.

• Melee Combos:
  Horde Clear: Push Attack-> Light-> Heavy-> Repeat, or Heavy-> Light and Repeat
  Single Target: Servoskull Ping-> Special Action-> Light-> Heavy and repeat 

For our blitz, we take the Artificer Servo-Skull with Medicae Servo-Skull, Purgator Servo-Skull, and Noospheric Command . It will passively thin out enemies around you, and you can sic it on a long-range target while waiting for your gun to refill. Make sure when using the Medicae Servo-Skull you see the skull highlight your ally in green, since we're also taking the flamer skull. With Purgator Servo-Skull, use it with Voltaic Emitter to melt armored enemies like butter; brittleness applied from System Shock with make their burn ticks devastating. For any carapace enemies walking in late, just special action with your melee. Noospheric Command makes up for the poor single target damage of this build into individual Crusher enemies and bosses.