Lone wolf crusher all rounder melee arbites
 Arbites Build - Warhammer 40k: Darktide 

This build excels at crowd control, survivability, stagger and has good damage into everything including bosses, with solid elite and horde sniping as well.

A standout of this build is the talent concussive, this talent makes it so that weakspot hits make an enemy count as staggered. This allows blessings such as no respite and skullcrusher to be applied without actually staggering an enemy, as well as your 10% vs staggered enemies aura. This means that you are an excellent damage amp, allowing arbites poor boss damage to become comparable to some psyker, ogryn and vet builds while also helping your teammates deal more damage as well. We also take execution order and its modifier keeping protocol to help our boss damage, along with monstrosity hunter you now gain 50% boss damage and 20% ogryn damage.

The gameplay loop of this build is simple, enter melee combat and control hordes with the crusher, use break the line to reposition, stagger larger enemies such as bulwarks, crushers, maulers, etc or close distance on ranged elites. Use shotpistol to block ranged attacks while aiming, includes melee attacks as well so you could snipe a trapper while surrounded by a horde without getting hit. You can also use BTL while looking down at a downed teammate and stagger all enemies around them to revive them. You could also use your replenishing arbites grenades for this, horde clear, boss damage and elite sniping.

Note that the crusher’s shove attack is very powerful with high crit and headshot damage and should be used very often. Also no respite stacks, up to seven times if a target is fully staggered/140% damage after one headshot with the crusher, the same is true for skullcrusher stacking up to 8 times or 80% damage, 4 stacks per hit , so max stacks reached with two crusher headshots.

Notable features

Toughness regen

5% on melee kill

5% on close kill

BTL can restore all of your toughness depending on how many enemies you stagger with it

Execution order replenishes 15% on marked enemy kill

10% over three seconds after spending one stam

Damage resistance 

3% against melee damage per human enemy staggered, non human enemies grant 5 stacks max 5 stacks/15% DR for health and toughness

Toughness DR

15% from lone wolf

20% on staggering three or more enemies 5s

Evasion

+1 effective dodge, 4 on crusher post talent

+25% dodge duration

How to fight a boss, with a team, you will likely be focused on horde clear keeping your teammates safe to fight the boss, you should try to keep up skullcrusher/concussive as well and stagger the boss with your grenade.

In solo or if someone else is horde controlling, use crusher to headshot boss twice proccing skullcrusher, no respite and your aura, use BTL, throw a grenade at the boss, doing large damage and staggering them, swap to shotpistol and aim for 5 headshots, landing all pellets of one shot will also proc full bore buffing your damage.  Your crusher also does significant boss damage especially on crits and shove attacks. This will do large amounts of damage to every boss in the game, consider taking carapace damage on shotpistol for captains and pack masters. Otherwise you shouldn’t shoot crushers so its useless.

I appreciate any feedback on this build as it is what i personally run on arbites