Chainaxe Chad
 Veteran Build - Warhammer 40k: Darktide 

The quintessential melee veteran, for people who don't want to play zealot, because screaming religious fanatics are cringe. Unusual to say the least, as so far, I've never seen anyone else run this, but it definitely works!
Used in both Auric runs and hard mode twins, this builds only weakness is closing the distance as fast as charge zealots and bullgryns can. There is somewhat of a solution to this problem however! 
Keep reading, dear Veteran.

I've spent around 40 hours playing this particular spec, which all started with me getting a perfect 550 Shredder Autopistol. A weapon I had so far slept on pretty much since the beginning. 
However, this weapon has the ability to stagger gunners, specials and maniacs pretty effectively and more or less immediately. While its damage leaves a lot to be desired compared to the Bolter or Plasma gun, it makes up for it, with its quick bursts, great ammo pool and fantastic mobility. This will effectively be your back up weapon for when you need to close the distance. You'll be fighting up close and personal with this build. This is a melee support/special killer build, so you won't be clearing hordes, unless your dodge game is in good working order.
I opted to focus almost exclusively on health from Curios, as you'll be able to instantly restore your toughness +50 bonus toughness, while at the same time stunning or knocking over any opponent around you, if things get too hairy.

Monsters:
You'll carve fat chunks of health from any kind of boss you'll face. Make good use of voice of command to stun plague Ogryns to stop them from stomping or charging. The chaos spawn is likewise easily dealt with. Same tactic of using your voice of command as a tool applies here, as you can stop it from grabbing you or save another player who has been grabbed by it. 
The only boss you'll have to deal with from afar is the beast of Nurgle, as it will eat you. This animation has no build-up and is, to my knowledge, not possible to stop with Voice of Command. Here you'll have to settle with peppering its bit yellow weak spot. 

Crushers:
Die from 4 regular headshots, five non-crit body shots or two charged hits with the chain axe. The 17 bleed stacks will kill one rather quickly, if the crusher gets outside your range and you only get to hit it once with your charged hit. You can break crusher overhead animations with your charged hits. that is an instant downer, even with 250+ health and 150+ toughness. It pays to play aggressively with this build.

Reapers:
Die from one regular hit and one charged hit or simply a critical charged hit. Something that will happen often with the bloodthirsty blessing. 

Bulwarks:
Die from two charged hits to the body with bleed damage taking care of the final inkling of health they have left. 

Mutants:
Die from a single charged hit. Attack it mid charge, as chain weapons stick to targets, almost irregardless of how far it runs past your range.

Specials:
All specials die from one or two regular hits. 

Berserkers:
Both types get stun locked from one to two regular hits and often, but don't always die from that. Otherwise, they get instantly stun locked from a charged hit and die. 

General enemies
All trash units die from one hit.