Soulblaze / Inferno Staff Psyker (Current)
 Psyker Build - Warhammer 40k: Darktide 

This is my current favorite Psyker build in the game!

Short Link: https://youtube.com/shorts/YjPRPVsNx8M?feature=share

Pros: Great crowd control and AoE damage. Very high mobility and toughness regeneration.

Cons: You can still get one shotted by certain things.

Weapons

For this build any melee weapon with Uncanny Strike will work well because our damage is primarily dealt through the Soulblaze damage over time effect. 

You definitely want to run the Inferno Staff if you're using the talent setup that I'm proposing in this guide, but an argument can also be made for the Voidblast Staff if you dislike the Inferno Staff. On the Inferno Staff you have to take Blaze Away nowadays because mob HP has been buffed to a point where you need every damage increasing advantage that you could get. You also take Warp Nexus because critting is important for your damage and survivability for so many different reasons. Inferno Staff also staggers and suppresses nearly any enemy it hits, so I see it as the better option for survivability unless you're an absolutely CRACKED player who is a master of the swap cancel tech.

Curios

For the Psyker you always want to run a fully defensive setup and take 3 Toughness Curios while stacking Ability Cooldown, Extra Toughness, and at least one extra stamina regeneration, block cost reduction, and sprint cost reduction. You shouldn't need Gunner Damage Reduction with this build because if you're playing it correctly you will never get hit by gunfire.

Talents

Some of the best talents on the Psyker are available to take right away. Take every node at the top except for Warp Expenditure and Battle Meditation. The reason why we don't take these two is because you will only have your melee weapon out about 30-40% of the time and you don't want to quell more peril than you have to - we love stacking peril with this build. Every node we take at the top increases our damage and survivability drastically.

For our Blitz we take Brain Rupture and Kinetic Flayer. This allows us to snipe targets that are too far away for us to reach and Kinetic Flayer can be buffed to do comparable damage to a Krak Grenade on the Veteran with all of our different sources of Warp Damage Increase.

Souldrinker and Empyric Shock are our next talents and they allow us to have more crit, more toughness regeneration, and more damage. You'll be left clicking a lot with this build so Empyric Shock is going to give you a TON of value.

Our Aura is Seer's Presence and we take Psykinetic's Aura for the cooldown reduction. Cooldown reduction is good in this game and every build should embrace it.

Next we take two BIG defensive talents: Empathic Evasion and One With The Warp. This allows us to count as dodging whenever we crit, which will be a lot, and increases our toughness damage reduction when we have higher levels of peril. We love peril.

Venting Shriek will quell 50% of your peril and Creeping Flames applies 6 stacks of EXTRA SOULBLAZE which can be applied on top of the max stacks of Soulblaze that you've inflicted on any given target. Additionally with enough damage increasing effects these 6 stacks of Soulblaze can just be spammed every time Venting Shriek is up to clear every Horde Enemy on the screen. We have to take Becalming Eruption but honestly if we were able to, I would skip it.

Vulnerable Minds and Warp Rider give you a hefty damage increase, these are always worth taking.

Solidity and Puppet Master are very comparable, you could honestly take either or and I wouldn't blame you. Puppet Master may be the better option when playing in Havoc with a coordinated team while Solidity is a safer option for players who are carrying Auric games. Think about the synergies that either talent provides and choose the one that will benefit your playstyle the most.

Lastly for our Keystone we pick Warp Siphon because it works very well with Soulblaze damage and cooldown reduction for Venting Shriek. Essence Harvest provides us with even more toughness regeneration while In Fire Reborn will allow you to stack up your Warp Siphon stacks very quickly.