Bundles's Ball Dispenser Psyker
 Psyker Build - Warhammer 40k: Darktide 

I've got balls of steel! (to dispense)

Do you like bowling? Do you wanna see every enemy fall before you from a distance, even Crushers? Are you tired of using the Inferno Staff? If you answered yes to any of the previous questions, you'd probably like the Equinox MK IV Voidstrike Staff!
Jokes aside, this thing is shockingly strong with the right setup, and this build aims to take advantage of that. This build is centered around one thing, and that is Crits. Crits with the staff's secondary fire allow you to mow down everything, including Crushers and even bosses. Before we get into breaking down the build, some tips to know about the staff itself.

Playstyle & Charging 

Generally, you're going to be wanting to play away from the frontline with this build. Being able to make space is very important for this build to function. If the horde gets too close for you to safely deal with incoming threats, either toss some Assail shards or whip out your melee weapon of choice and either make space or kill the heretics. Assail shards should also be used for trash-killing assistance, softening up ranged enemies, sniping specials, and dealing with multiple spaced-out threats.
As for charging, for regular hordes and packs of unarmored enemies, you're gonna wanna charge around the 30-50% range. This will usually be enough to wipe out hordes with just a few blasts. For Crushers, packs of armored enemies, or mixed hordes, charge around the 50-95% range. Fully charged shots take too long to charge and are usually not worth it in most cases. With just a few crits, you'll be able to quickly kill anything that stands in your path thanks to the multitudes of crit-oriented buffs this build contains.

Weapon Choices + Perks and Blessings

Obviously, the Voidstrike staff is going to be our ranged weapon of choice. For blessings, Surge and Warp Nexus are the only blessings you should run with this build, as they are why this build even functions in the first place. For perks, ranged crit chance is a must, and I recommend taking Damage VS Carapace for the ability to mow down Crushers for efficiently. You could also choose Damage VS Unyielding instead of the carapace damage boost if you want more boss damage.
As for melee weapons, generally take a lightweight weapon that can do decently well against armored enemies. My personal recommendations are the following: MK III Combat Blade, MK IV Dueling Sword, and MK VI Combat Blade. You can also use the Deimos Blaze Force Sword if you prefer your melee Warp-flavored. Your melee weapon should mainly be using for clearing trash that has gotten too close, dealing with closeup elites that don't allow you to make space, and for mobility/repositioning.
 

Notable Talents

• Scrier's Gaze is the most important part of this build. Always pop this whenever a group of armored enemies appear. This will allow you to maximize crits and the ability to deal with armored hordes. Precognition's Finesse damage increase can allow you make lightwork of Crushers. Only stipulation for this ability is that it can be a bit hard to manage your peril while Scrier's is active, but practice makes perfect.
• Psykinetic's Aura is incredible. Thanks to the (currently recent) Talent tree rework, we can slot in Psykinetic's Aura alongside Assail. Thanks to this talent, it is possible to actually maintain Scrier's Gaze at all times, provided you kill enough elites. More Scrier's means more damage, so this talent is fantastic for this build.
• Empathic Evasion is very nice to have since you're going to be getting crits a lot with this build. But, if you feel like you don't need it and want to abuse your dodges more, try Anticipation instead.
• Battle Meditation makes managing your peril with Scrier's much easier.
• Mettle and Perfect Timing are self-explanatory.
• True Aim is fantastic thanks to the excellent Voidstrike Staff's horde clear potential and, of course, crits.
• Disrupt Destiny will be our keystone of choice thanks to its crit synergy. Lingering Influence is the more valuable modifier compared to Perfectionism, as you're going to want to maintain max stacks for as long as possible.
• Assail is taken for the reasons mentioned earlier, which is dealing with gunners, trash-killing assistance, special sniping, and spaced-out threats.
• Warp Splitting can aid in enhancing your already strong horde clear potential if you prefer Staff focus.
• By Crack of Bone can be used if you want to quell peril while remaining in combat.
• You can swap out Warp Rider for Vulnerable Minds if you want more consistent damage against Ogryns and Bosses.
   

Additional Notes & Conclusion

I usually run 1 wound and 2 toughness curios, but if you feel more comfortable playing at 2 wounds, then you can run 3 toughness curios instead. Some might ask why I didn't take Smite, and that's because Assail contributes to killing key threats. Smite kinda sucks without Empowered Psionics, and we're not taking that, so Assail is overall better for this build.
This build is Auric-viable and has very high damage output when played properly. You could probably reliably clear Auric Maelstroms with this build if you and your team are good enough. I have not personally tested this build on high Havoc, but you can try to make it work there if you want.
Remember. you are a Psyker, and you should stick with your team if you value your life and safety. If you get caught out in a bad position with no easy way to reposition, it tends to be a lights-out, so stay with the team so they can protect you and give you the space you need for your damage potential.
Now, go out there and give those filthy heretics a good Strike!