Novice's 2.0 Havoc 40 Tested Build
 Psyker Build - Warhammer 40k: Darktide 

Playstyle:

This guide/build is heavy centered around high Havoc, and prioritizes correct positioning, deploying as many bubble shields as possible by decreasing cooldowns, repositioning via the Deimos sword (push attack/Deflector blessing/Kinetic Deflection) talent, getting clutch revives (Deflector/Kinetic Deflections /Ally revive speed curios), and most importantly, melting hordes of enemies. 

Talents: 

Most of these talents are non-negotiable to me as they feed off of critical hits, cool down reduction, and overcapping soulblaze.

One with the Warp (toughness damage reduction) can be taken if you remove Warp Battery (6 warp charges). I switch these depending on how I'm feeling, no real rhyme or reason. Sometimes I'm playing great and I want the extra warp charges for more shields, other days I can see myself getting hit by more bullets so I want One with the Warp. 

Wildfire is probably the one people look at and say it's not good, however, I find that it's serves two purposes; one for getting Warp Charge stacks with In Fire Reborn, especially if I can't focus at one direction for too long, I can at least spread my fire to multiple areas and have that spread continue due to wildfire which will also net me stacks.  Wildfire will also occasionally proc kinetic flayer, which will help me execute enemies further away, or continue the domino effect of burning hordes in front of me / overcapping soulblaze with Perilous Combustion. 

Weapons

Deimos MK IV Blaze Force Sword: 

Perks and blessings: I take Stamina and Maniac on my sword for multiple reasons; taking stamina on my sword allows me to take another curio of my choice, and maniacs are for mostly killing dogs and mutants that can force me to break my position. 

The Deflector blessing is great for helping you reposition, especially when you're faced with a lot of range. You can hold your block and either bide time for your shield, reposition yourself to safety, or both. There is opportunity cost here; you could take the dueling sword instead, but in Havoc, I prioritize staying alive and repositioning. I have my team that can help me kill things like Crushers, so I'm more willing to give up dueling sword. Pair this with block efficiency and Kinetic deflection, and you can block / push your way to a beter position for you and your team. 

This is also why I put Stamina and Maniac damage as Perks on this sword as well; since I know I won't be melee-ing Crushers/ Bulwarks / Melee enemies in general often, I don't mind putting stamina to open up other curio options, and Maniacs' so I can kill Mutants and Dogs quickly (Mutants in particular and important for me to dispatch because they can affect positioning)

Inferno Staff/Talent tree discussion: This staff melts nearly everything in front of you. With my currently talent tree setup, it's easy to stack soulblaze, break soulblaze cap with Perilous Combustion / Kinetic Flayer, and keep my warp charges high. 

I've been asked why I keep Empyric Resolve (-40% peril generation), and my rational is that while it does take longer to get to higher peril to do more damage, it's easier for me to stay in the 70-90% zone and have a lot more output while I'm in that zone. Especially in Havoc, it's very easy for me to float in-between 70-90% and have as much output as possible. I also take wildfire because although it's known that the damage is shitty, the ability to spread more fire onto targets also increases the chances of gaining Warp Charges, and can also proc Kinetic Flayer, which has the potential to create a domino effect where soulblaze can stack to 32 instead of 16. 

Curios

I usually run all Health Curios with Combat ability regeneration, Ally revive speed, and Block efficiency. 

I run health curios instead of toughness for high havoc because 3 toughness curios only nets me 30 extra toughness, when HP gives me a lot more room for error. I tend to stay in my bubble as often as I can, so I don't experience too many issues with toughness. 

I will trade Ally revive speed for corruption resistance when needed.  Block efficiency and ally revive speed work together with Kinetic Deflection to get ally revives in the middle of crowds, which can come in clutch when you're one of the last member's alive (this happens often due to Psyker's being in the backline more often, which in turn keeps you less susceptible to getting downed. Combat Ability Regeneration is for more bubbles.