The Soulblaze Psyker
 Psyker Build - Warhammer 40k: Darktide 

With this build you effectively act as the team's glory hound, bounce around spreading as much flame as possible with your inferno staff to given Wildfire as much of a chance to take effect as much as possible, and then swap to your Obscurus to take advantage of your high peril to cleave through the now enflamed horde. 

When dealing with Elites, I've found it's best to use the Obscurus Force Sword with a quick charge of it's special attack, followed by a heavy attack on the target. The majority of the time this works as a quick and easy kill, especially on anything Mutant sized, and lower. 

For anything larger than Mutants, excluding Reapers as their health pool is within the sword's damage threshold, swap back to your Inferno Staff and apply Soulblaze for the continuous chance to activate Kinetic Flayer, once Soulblaze is applied swap to Brain Burst, and simply pop their skull. At max Empowered Psyonics this should only take one maybe two uses of Brain Burst to get done, excluding Monstrosities.

When dealing with Monstrosities, put distance between you, and the beast, and repeat Brain Burst until it's dead, with Empowered Psionics you deal a solid amount of damage, but it's not your role to focus them, you'll need your team's support to finish the job, unless you're just him.

That's about it, remember to deploy your shield for cover, and put the revive speed to good use to carry the Zealot.