Psykic Slasher
 Psyker Build - Warhammer 40k: Darktide 

Playstyle

It's a very pure melee experience. No gimmicks or tricks, just plain raw melee. You'll spend your focus on hitting your Heavy 2 against Carapace, continously dodging, and quickly taking out approaching disablers while still engaged in melee.

You're very fast, you deal insane damage, and you're surprisingly tanky (as long as you keep fighting).

Build

Toughness Regen

With Warp Expenditure (15% over 3s), Mettle (10% over 4s), Souldrinker (15% over 5s), Scrier's Gaze (2.5% per second), Disrupt Destiny (25% over 2.5s) you can end up with 23.5% toughness regen per second.

Peril

You'll be at max Peril almost always. We don't take any peril reduction talents and we don't use any abilities that generate peril. We build up peril via Just a Dream and just enjoy constant +20% damage, +100% cleave, and 33% toughness damage reduction.

Scrier's Gaze

Sometimes I use it for extra damage, but its main use is as a defensive ability: 50% peril quell generates toughness instantly, you generate additional 2.5% toughness per second, and it gives toughness damage reduction. I'll run straight into a horde of gunners with this active and its fine.

This build deals strong baseline damage so just keep Scriers Gaze ready for when you're in trouble. 

Disrupt Destiny

Usually it'll mark enemies closest to you, and with the extra stacks on weakspot kills it's quite easy to keep up 20+ stacks on average. You don't have to actively think about it, just go for the highlighted enemy when possible and you'll have decent stacks. Use the Uptime mod to track your stacks https://www.nexusmods.com/warhammer40kdarktide/mods/573

Weapons

Deimos Mk IV Blaze Force Sword 

It's extremely fast, and Heavy 2 attack has insane stagger knocking over Crushers with ease.

Spam light attacks for hordes. Use the Heav Heavy attacks against Mauler/Crusher.

You can also easily dash between gunners with a charged heavy attack.

I don't ever use the special. You get stuck in the animation for too long and it doesn't to enough damage. 

Accatran MG Mk II Heavy Laspistol 

Seriously underrated weapon. Extremely quick, but still packs quite a punch.

Main use is taking out specialists and disablers, often via a single shot that procs Kinetic Flayer . 

You can also take out a mob of gunners or even a horde of reapers: Perilous Combustion + Inferno blessing make it pretty easy to take out large groups of ranges elites.
Or just shoot a boss for decent DPS.