Devil's Claw Scum
 Hive Scum Build - Warhammer 40k: Darktide 

This is the most fun build I've played for what's currently my favorite class. Devil's Claw sword is just supremely satisfying due to the parry mechanic, high cleave, and versatile attack combos. Its big weakness is crushers, which are nicely countered by the needle pistol. The build can really handle anything: boss spam, elite spam, dense hordes, special sniping, clutching, and reviving under pressure (with Forge's Bellow or Boom Bringer).

You can dump either Mobility or Cleave Targets on the sword. You gain 1 cleave mass on heavies and less than 1 on light attacks going from 60% to 80% Cleave Targets, whereas going 80% Mobility significantly increases your movement speed; I prefer maxed Mobility. I take Skullcrusher instead of Rampage blessing because the build has power bonuses from Rampage! ability and cartel stimm, as well as 2 stagger pulses from Forge's Bellow per ability cooldown, so it's decent at staggering most enemies and Skullcrusher is a much larger damage bonus when it's active. Forge's Bellow even staggers monstrosities, so it's great to stack up Skullcrusher for a quick beatdown.

Needle pistol is the answer for crushers and anything you need to kill from range. It's also good for preloading toxin stacks before going into melee with bosses/monstrosities. You have unlimited ammo from Pickpocket on Auric/Havoc, so spam away. Rocket launcher is the answer for groups of armored enemies or general death-ball situations.

You can swap a +3 stamina curio for toughness or health if you want more defense. 3x4% ability cooldown perks only gives ~2.8 seconds cooldown reduction after factoring in Chemical Dependency, so I opted for health perks instead. My curio setup is for intended for Auric missions and may be too spicy on Havoc with the health/toughness penalties.

Hyper-Violence is great with high enemy density, but does basically nothing when density is low. This is a flex point that can be swapped to The Sweet Spot (~13% overall damage bonus on weakspot hits with Devil's Claw), Chem Fortified, Nimble or whatever you want.

On the cartel stimm, all of the strength capstones are good. Finesse damage has the highest average DPS, although crit chance can help proc Hyper-Critical more often. Rending is probably the weakest path since chem toxin has high baseline armor penetration already, and 15% rending isn't going to be enough to make the Devil's Claw strong against crushers. On the other hand, rending is the best pre-buff for the rocket launcher if you want the juicy killfeeds.