Lightning Burst Psyker
 Psyker Build - Warhammer 40k: Darktide 

This build is very much an "All-rounder" type of build, with tools designed to work in any scenario. It specializes in team support and elite/special killing, and popping out bubbles like its going out of style. This is a support playstyle, with very high damage and cc output.

Loadout:

Illisi MK V Blaze Force Sword

•  is, when it gets powered up, an absolute buzzsaw for chewing through hordes. With max stacks of Slaughter, building Unstable Power though either casting abilities or the using the staff, and using the Weapon Special Ability to increase your damage, you can tear through hordes of enemies with relative ease. It's not as powerful as it was pre patch 14, where the sword had infinite dodges, but with 5 it is still very easy to maneuver around the battlefield. 
• The sword is your only real source of clearing mobs, as the staff and blitz ability are for elites/specials and priority targets.

Nomanus Mk VI Surge Force Staff

• This staff is, hands down, my favourite staff in the game. I would regularly run this for the incredible crowd control and it could singlehandedly turn any Damnation game into a walk in the park. Since Patch 14 the staff has lost the majority of its chain stunlocking power, but it received a very nice damage boost to make up for it. Rather than tickling that pack of Crushers you can now kill them in two to three charged attacks, vastly increasing your damage output. 
• The Surge staff is your main source of damage with this build, for clearing shooters and the odd poxwalker to taking down most elites/specials with one or two charged attacks. If a horde makes it through the lightning gauntlet, shred them with the force sword.
• The combination of Warp Nexus and Warp Flurry mean that when this staff gets going, it really gets going. The increased Crit chance and charge speed mean you will be dishing out more damage in less time, and most elites and specials, apart from Mutants, Maulers, sometimes Ragers, and the big ogryn bois, will go down in a single charged attack.
• Can still dish out very good cc, but just not as strong as it used to be.
• Be mindful of your peril, as with spamming charge attacks it's easy to overload yourself.

Brain Rupture

• This one was a bit harder for me to settle on, but I really like the 'ol bb right now. When paired with Empowered Psionics every elite kill will grant a charge, which increases the damage, charge speed, and removes the peril cost of the ability. Combine this with Kinetic Resonance and when you put down your bubble your Brain Ruptures are even stronger.
• This is your long range elite/special sniper tool, as well as your primary source of boss damage.
• In comparison with Smite and Assail, I found that Brain Rupture pairs best with this build. Smite is fun, and is amazing for its cc value, but the damage is still very weak, leaving the enemies alive once you have to quell, unless you have a teammate on standby while you stun. Assail on the other hand, is very fun and cool, but while the right click throw had its damage boosted, it still takes multiple throws to take out most elites and specials. 
• Ideally you should save your Brain Rupture casts for when you have Empowered Psionics, to take advantage of the buffs. 

Telekine Shield (Bubble)

• Probably one of the most useful abilities in the game, and pairs super well with this build.
• Gameplay loop is pop bubble at the start of combat, kill elites and specials to reduce cooldown, rinse, repeat.

Psykinetic's Aura (Node)

• A cornerstone of the build. Each Elite or Special you kill reduces all party cooldowns by 5%. With the volume of Elites and Specials on the Auric missions, the more you kill the more bubbles you can pop down for your team. Super useful.

This build is very powerful and can do everything you need it to. The only thing it really falls short in is horde clear, since without the aoe damage of some of the other staves you won't mow them down like grass because your melee weapon is your horde clearing tool. That said, I find this sword to be the best for hordes as you can usually one-hit headshot most horde enemies when you have enough buffs stacked up. Be mindful of your spacing and positioning at all times so you can keep on zapping, tossing out a Brain Rupture on those pesky distant targets.