I am speed
 Psyker Build - Warhammer 40k: Darktide 

The autopistol's only job here is to be a free approach option into any group you want:
It provides full immunity to bullets while sprinting and shooting, which can be VERY fast with this build. This will replenish a fair amount of toughness in the process with inspiring barrage. Prioritize shooting blue enemies to get there faster, this is basically Fury of the Faithful at home. Terrifying barrage exists to shut down the entire group of gunners upon killing a single guy on your way over to them, allowing you to pick apart the rest without worrying about getting shot or your allies getting shot. Deimos can handle any enemy in the game, it can struggle with hordes at times though. Just intermittently throw in a few assail shards while attacking hordes to thin them quickly. Kill a group, move to next, repeat. Use lock on assail to deal with far away gunners or snipers.

Notes on the Deimos:
Initial light hits nearly as hard as initial heavy, but is WAY faster and is not committal in any way. Great at dealing with captains since you can block them basically forever.

While Scrier's is up (and in general) just try to get as many headshot kills as possible, you can keep up Scriers for an absurd amount of time doing this.

You can light out of block in the middle of rager chains and block again before the next hit take down ragers quickly/safely at no risk.
Heavy 2 and the force push follow up throws any non boss non mutie enemy to the ground (some captains will still be thrown around by heavy 2). It also one shots Muties with a headshot.

The force push follow up can break bulwark guards, light into heavy 2 puts them on the floor, then just keep using light-heavy until it's dead.

Using empowered attacks also break bulwark guards, even on a light. This is pretty noncommittal and does respectable shield/stagger.

Light-Heavy into any armored enemy. Horde is just light repeating or heavy light repeating. Its about the same, I find light repeating is easier/safer. Once you get stacks of DD or have Scriers up, you're one shotting all chaff enemies regardless of where you hit them. Use intermittent shards to thin hordes.

If you find yourself out of position (or a bunch of reapers just came around the corner) throw up block and dodge/push your way through a horde to safety. You can hold block pretty much forever as long as you're not getting overheaded or disabled.

If you have the time, empowered heavy does great boss damage and shield damage. If not, either light poke between blocks or light-heavy chain.