Electro Support Skitarius
 Skitarii Build - Warhammer 40k: Darktide 

The general idea here is to spam Voltaic Emitter on cooldown to apply electrocution to all enemies in a wide area, which stuns, deals damage over time, and sets them up for chaining arcs from Branx Mk III Arc Maul and Branx Mk IV Arc Rifle. Because we're spamming the ability, it doesn't seem worth investing in things that scale with current charges, such as Voltaic Arcs and Voltaic Motivator. System Shock stacks up to 40% brittleness from all sources of electrocution, including basic attacks from the Arc Maul and Arc Rifle, so you'll be applying tons of brittleness to scale your team's damage.

This build uses ranged and melee combat roughly equally. Branx Mk IV Arc Rifle has a large magazine but slow reload, so it's usually optimal to blast some enemies and then switch to melee and let Gunsmith automatically reload for you. Hybrid Combat Covenant rewards you for swapping between ranged and melee frequently as well. Ammunition-Restoration Pod regenerates 1% max ammo/second and you have +35% max ammo from Ammo-Cell Augury and Ammunition Deposit, so you can be fairly trigger-happy without running low on ammo.

Power Overload gives nice buffs to your whole team and procs pretty frequently during combat. Static Capacitor Drain provides huge value if you can avoid dying during a mission. I didn't take Powerdrive because it only gives 1 extra overload per 6 ability uses, equivalent to 5 trash mob or 2.5 elite/specialist kills by your entire team in coherency, which doesn't seem worth a point. Critical Power Overload is potentially good; the reason I decided to skip it is that you won't always be in melee range when you overload due to the hybrid playstyle of the build.

Due to Voltaic Restoration and Invigorating Overload, your whole team in coherency restores 20% toughness both when you use your ability or proc Power Overload.  The build has good support potential with damage and TDR buffs from Power Overload, AoE stuns from Voltaic Emitter, efficient brittleness spreading, frequent toughness sharing, and clutch revives with Medicae Servo-Skull. It also has a good amount of personal toughness recovery and TDR to make it a durable frontline build. You could swap out Galvanized Coating, Ammunition-Restoration Pod, Galvanic Marking Array, or Threat Detection Imperative to take Power Overflow for even more toughness sharing if you want.

I usually recommend revive speed perks on curios, but since we have Medicae Servo-Skull I think it's more useful to take cooldown reduction perks for more ability spam. CDR perks on curios reduce the amount of capacitance needed for an ability charge. 3x4% CDR perks means you gain a charge at 88% capacitance instead of 100%.

If you don't like the Arc Maul, Munitorum Mk III Shock Maul is a good alternative. The special attack stacks 40% brittleness from System Shock in one activation and is good for disabling elite enemies and shredding captain voidshields. Light and heavy attacks apply the electrocuted status on staggering hits. It also has the Skullcrusher blessing to scale your team's damage against affected targets. I recommend either High Voltage or Hammerblow for the second blessing.