IMA FIRIN MAH LAZAH!
 Veteran Build - Warhammer 40k: Darktide 

Krak Grenade used primarily to deal with Crusher , but in tense situations you should use it against Bulwark , Scab Mauler Scab Plasma Gunner and Scab Rager .
Superiority Complex , Bring it Down! and Grenade Tinkerer are necessary to have oneshot breakpoints against Havoc 40 Crushers.

Achlys Mk VI Power Sword serves as backup weapon against Crushers, but mostly going to be used to deal with enemies with Carapace heads, like Maulers and Plasma Gunners. Use Kraks against last ones if they're standing too far to engage in melee. Especially effective if you throw Kraks at the group of Crushers while running towards them and right when they detonate you start slashing them with melee. Very satisfying to pull off.

Kantrael Mk IIb Infantry Lasgun is against everything what's not Carapace armored.
Pair Deadshot with Executioner's Stance as much as you can, since after recent patch, Mk IIb variant now has much lower recoil, and Deadshot with Executioner's Stance allows us to spam shots with pin-point accuracy like Accatran MG Mk II Heavy Laspistol .

Not using Duck and Dive because otherwise would be impossible to min/max Power Sword efficiency, so having +2 Stamina on weapon's perk, +3 Stamina on Curio and a bunch of stamina management perks would allow you to not drain ur stamina fully, since our gun shoots fast and Deadshot drains stamina in points while Tunnel Vision recovers it in percentage, so increasing max stamina will affect Tunnel Vision, and to increase it's potency even further we take Withering Fire which allows us to cleave through additional small targets, possibly giving us 20% stamina back per shot and in addition if your shot did hit 2 targets in weakspots and it wasn't a crit, we'll get 2 stacks of Headhunter instead of one.
Sprint efficiency was taken because we're spending a lot of time sprinting and stamina is crucial for us. 
Block efficiency is ignored because we are the one who pushes melee contact, not enemies.

Survivalist was ignored because we already have huge amount of ammo, plus with all crit chance we have (10% Vet base + 5% Infantry Lasgun ADS + Deadshot + Reciprocity + Headhunter ), Shock Trooper will be super efficient... and other Veteran players almost always run Survivalist anyways.