Extreme melee scum
 Hive Scum Build - Warhammer 40k: Darktide 

[Updated for 1.10.2] The Improvised Mk I Shivs are the crux of this build. Being able to attack like a blender through hordes and elites feels so good. The needle gun is for snipers and for running at gunners.

The stamina curios are to increase your attack speed with Swift Endurance . With three +3 curios, you are getting +26% attack speed basically always (3 base, +1 from shivs, +9 from curios, times 2%). Additionally, you can block an absurd number of attacks while picking up teammates. Careful with that interaction with your ability ending. While you stop hitting people, the ability will end and drain your stamina. You can dodge one regular gunner for like 40% of your stamina with Regained Posture, which is very necessary. You can get the curios by spamming the Mystery Acquisitions at Melk.

In play, you are using the shivs nearly 100% of the time. You are dodging around the edges of the horde spamming light attacks at their heads. Or you can just run through the horde faster than they can catch you, dodging as appropriate. When you get surrounded by crushers, just pop a Blackout at your feet and find a better position. Carapace gets heavy attacks to the head instead. Ragers should be going down in one heavy attack or a couple lights while Rampage is up. Hordes of Ragers can be dealt with easily with the increased dodge distance or just using Rampage to hit enough light attacks to kill them before they can do anything to you. Throw a knife when you remember that's a feature of the shivs, then forget about it again for 5 minutes.

The gun comes out when you need to sprint up to the gunners. If you're out of stamina to proc the ranged immunity, dodge until you have enough, then sprint. I guess it can also deal DoTs to bosses and carapace-armored scabs, but at only 6 bullets in a clip and at least 3 to take out a Crusher, it's better to spam heavy attacks.  Run 'n' Gun is just so your left finger has something to do while you close the distance.

Alternative talents: If you want a couple changes, I would drop Channelled Aggression first and either Hyper-Critical or Long Lasting second. Potential talents to take instead are Slippery Customer or Like the Wind. I don't dodge-slide, so I don't take the former, and your gun takes care of gunner spam.

I also suggest the Skitarius mod to keep your trigger finger healthy. Using the stim and Rampage gets... difficult to keep up with the melee attack speed.