Warp Phased Assailant
 Psyker Build - Warhammer 40k: Darktide 

This build is based around alternating assail and electro staff for burst damage. (Having a fast&comfy keybind for activating shards is HIGHLY recommended)

It allows you to use assail or staff conditionally as either (assail vs) light hordes or (staff vs) heavy armored as necessary.

Fire 1 or 2 regular shards, followed by a rightclick shard, then immediately swap to electro staff.

Swapping weapon after alt fire on assail shards will skip the cooldown allowing quick staff attacks to fill the gap, or to cooldown with staff quell bonus. Right click shards still do solid damage after assail damage was reduced, but suffer the equivalent of a cooldown/recycle time, as the arm animation re-prepares the shard.

Immediately after switching to staff either: cooldown quell holding staff, then rightclick alt/fire, or immediately alt/fire. A short charge up with the staff blessings will fill 1/2 <-> 2/3s fairly quickly after stacking, and will impede movement very little, along with Mind in Motion preserving your movement speeds the rest of the time. Direct fire primary shots for the staff are generally ideal for quick follow ups on stunned targets like trappers/hounds to ensure a quick finish, with little chance of missed/wasted shots. Alternating quickly between quell and 2 shocks is relatively smooth with this build, but you still do have slight timing gaps, so be ready to respond to trap type enemies immediately, even if it requires sending a few shards off in advance.

Optionally if needed you can tap a single shard and swap back to the staff for quick interruption of several light targets, the alternation between shards & staff is meant to preserve your ammo while maintaining damage while allowing shard's regen time to keep your multi-target ammo supply steady.

Damage and Charge Rate on staff are clearly most important, Critical does not have to be the dump stat, averaged stats are fine, but poor warp resistance/quell speed can make the weapons use as a steady crowd control tool more difficult. Attacks do not need to be fully charged, the build revolves around pace, acting as an interrupt effective against all targets but bosses and limited effect on mutants. Fully charging the primary should generally be saved for armored targets: bulwarks, crushers, maulers, armored rages etc, and is wise to effectively time full charge for the moment specials/elites come around corners to your LOS.

Your vent ability has several purposes, it is the usual OS button, this build generates peril VERY quickly, but saving it until it proves absolutely necessary or ideal moments of opportunity, is highly recommended, holding it in reserve reduces peril gen by 36% and damage by 24%, counting warp rider, if your careful and well timed, fighting with high peril during rotation is common.

Your sword is a reserve, not meant as your primary combat mechanism, it's meant to refill your dodge count, and headstrike then-> pushblock/dodge slide your way through tight spots. It can sub instead of staff, where you fire a few shards then melee to dice small/moderate light packs a tad faster, but is not this build's strong suit, if a pack numbers too many, your far better off using vent to DoT larger packs to thin it out then rely on melee to fight.