Psyker Veteran
 Psyker Build - Warhammer 40k: Darktide 

This build was thought when I had a great success with my Veteran with the Zarona Combat Shotgun and then I realized, wait, the Psyker have a lot of damage and crit bonuses that could also make the shotgun work, so after a few attempts and many games I finally nailed down one build that works greatly and wanted to share as this is, dare I say, even cooler than the Veteran version.

What will I do with this build?

You'll be a vanguard and a supporter with the ability to tear down specials hordes and specials either from close or from afar, lunge yourself into the hordes, crank that peril to the max and Vent the Shriek in order to revel in the slaughter that you'll enact with the toughness of the titans.

The melee weapon I do believe dismisses explanation, one of the best weapons of the psyker, the Covenant Sword is a powerful weapon with great cleave and damage and allows for super easy combos for crowd control, the only point is that the mark VIII requires a push attack in order to do a powerful carapace piercing stab, and since Crushers are the most feared enemy in this patch it will require some above the average skill in order to deal with them as Brain Rupture not only requires more attacks in order to be effective it won't be able to be used as often because of how much peril this build generate with each use.
Talking about peril one can use the sword's special action in order to generate huge amounts of peril while attacking, and by doing so allows you to both activate a full soulblazing Venting Shriek or to further increase the damage, although use only this tactic only if you know how to fight properly as your peril will also absorb a lot of the hits you take because of the Just a Dream talent.

Also about Just a Dream and Immaterial Focus, they are damage reduction, not only toughness damage reduction, this comes into two major points, one is that they also reduce the damage that would go into your toughness AND your health, so they have a double effect, and second is that damage reduction percentages are applied AFTER toughness damage reduction is applied, making it a multiplicative bonus into damage reduction further increasing your health overall.

I'm using Immaterial Focus with the keystone for extra toughness regen, I believe it may be better on this build than One With the Warp, but I can't really tell right now.

Now let's talk about the star of the show, the Zarona Combat Shotgun, one would question themselves why would they would use this weapon over a staff and the answer is just for variety, the staves are superior and don't require ammo but still the way the Zarona plays when you get used to how it works feel incredible.

The main point of the Zarona is its special shell that allows for a wide horizontal attack, alongside a blessing that allows for extra crit chance for each previously hit enemy and another that applies bleed with each crit, all enemies that survives the first barrage will soon perish. Also when a special dies the soul blaze will start to creep out increasing your crit chance and the chance to gain a stack of the Warp Syphon talent.

With the Zarona you can stay back raining special shots dealing the with the horde and specials, to pick on single enemies use the normal shot, specially against Reapers, a few headshots and they're history.

Then you'll want to start a battle dance, going inside the enemies with your outstanding toughness, increase your peril and appy soulblaze in order to get the  maximum bonuses from Malefic Momentum, shoot, reload a special shell and start it all over again. GG.