Mathematically Correct Arbites [Meta - Auric]
 Arbites Build - Warhammer 40k: Darktide 

Build goal:
Max out BM kill potential with PA -> Light -> Light -> Light horde clear combo against all enemies excluding ogryns/bosses.

(Note: PA triggers the "15% damage for 5s on heavy attack node)

With this build, you can consistently kill 4 shotgunners/gunners/bruisers/etc per swing, after the first 1-2 swings into a horde.. With LIGHT attacks!

8-12 kills per second from your melee alone into anything other than carapace/ogryns with maxed out move speed talents/stats, allowing you to move from horde to horde like a feral animal. Hotswapping to your shotgun whenever you see a thick pack of enemies cranks this up even higher.

It prioritizes damage nodes that provide %Total Damage on the *FIRST* swing, not on "staggered enemy" or "electrocuted/suppressed" enemy. This way, we can fully lean into Brutal Momentums one-shot capabilities.

You either take duckbill shotgun to compound your horde clear capabilities, or boltgun if you have issues against ogryns. 

I've done testing in havoc, and you can maintain almost all of your BM breakpoints all the way up into Havoc 40, but it *does* get difficult to survive without taking Forceful as a keystone. This is an Auric focused build.

Weapon choice:
Mk7 Tactical Axe was buffed somewhat recently to have the strongest lights out of any of the three options. Considering Arbites has an *incredible* amount of damage as a class, there's 0 reason not to prioritize light attacks, instead of trying to build a glorified Combat Axe by building around Mk2's heavies. The PA staggers ragers, and you can 2shot dreg/scab ragers without too much trouble, especially with castigators or k9c4 and your taxe dodges.

Note: Because Arbites has *so* much flat damage, we ignore building around crits. When you oneshot everything important anyway.. Crits become a little less important. (Breakpoints!) That is why I dump cdmg and go for 80 mobility instead - it just feels nicer.

Additional note: This build also works with shield and maul - but it's slightly worse. Shield/Maul is slower and has slightly less kill potential, although it has slightly higher TTK against carapace/boss enemies.

As for your secondary, I either go for the boltgun if I desperately need ogryn/boss damage, otherwise hotswapping to the duckbill shotgun for incredible chaff clear (and March) value / ranged enemy clearing value (as it has incredible range). Again, we don't take Scattershot because you have so much damage - crits really don't matter. 

Ability choice:

The correct answer is always Castigators, if you're running Execution Order, in my opinion.

With the cdr from your curio, your ability cooldown becomes about ~40s.

With the CDR from Execution order (assuming good uptime), your ability cooldown then becomes ~20s.

With the Castigators subnode Writ of Execution, you gain a stacking damage buff on elite kills that add up to a massive 50% damage increase - and it lasts the full 10s while you're in castigators, and an additional 10 seconds after your last elite kill. 

This means that you have a theoretical near 100% uptime on a 50% damage buff, while you're in a dense horde.

Additionally, Castigators already has an incredibly broken feature - the ability to ignore zoners and ragers, something that used to exclusively belong to Zealot's Until Death. Pop the stance and kill your way out of danger. Anything that allows you to resist being "darktided" is incredibly valuable.

BTL is still good, but these two incredibly broken features heavily outweight it in my opinion - especially considering that this build already comfortably gives you all of the movespeed you could possibly need.

Talent Choice:
Everything I have selected prioritizes things in this order:

Flat first-hit damage -> damage reduction -> toughness generation.

I was able to hit every single first-hit damage node, as well as every important damage reduction node, and almost all of the good toughness generation nodes.

If pressed, I would drop "No Lenience" (keystone subnode) for Target Neutralized or Force of Will.

Interchangable node:

If you struggle against Ogryns:
March -> Monstrosity Hunter

I personally get more kills with March as I move from pack to pack, and I also simply find move speed more fun. Arbites has a *lot* of utility between perma-stunning ogryns with the dog and using the K9C4 ability to stun a pack of ogryns, such that I find that I can work around them by killing chaff until the ogryns are isolated. This doesn't slow down my clear speed, and by the time I'm finished, the ogryns are either dead or alone and vulnerable.

I would only do this if you are using Boltgun instead of the duckbill shotgun.