Devil's Claw Zealot
 Zealot Build - Warhammer 40k: Darktide 

This build is designed to maximize the effectiveness of the Devil's Claw sword and its parry special action. Previously I recommended the Skullcrusher blessing, but since Grievous Wounds was removed from the skill tree, we can't reliably proc it anymore. Now I recommend Shred along with either Rampage or Wrath. Despite its description, Rampage is a power buff and will multiply your normal damage, cleave, and stagger bonuses. Wrath is better on Havoc due to increased enemy cleave mass. Cleave with Rampage will generally be good enough on Auric difficulty, but Wrath isn't a bad choice there either.

Since the sword is weak against carapace armor, the bolter is needed for killing crushers at a reasonable rate. Locke Mk IIb Spearhead Boltgun has more ammo and better DPS into crushers, but Locke Mk III Spearhead Boltgun will also work. Depending on how scarce ammo is on your team, you can either mag-dump them or just shoot them 4 times to max Shattering Impact and Puncture stacks before switching to melee. While it might be tempting to take a different blessing like Pinning Fire or Cavalcade on the bolter, Puncture activates the damage multiplier from Blinded by Blood, provides extra DPS against monstrosities, and helps finish off wounded targets, so I think it's best-in-slot for this build. The bolter will mainly be used against ogryns and monstrosities, which won't be reliably staggered to proc Pinning Fire. Out of Pocket allows you to avoid the slow reload by killing 10 enemies in melee.

Blades of Faith are used for killing most specialists/gunners outside melee range and for animation-canceling the slow bolter weapon swap; to do the animation cancel, start swapping weapons and then use a throwing knife after the bolter equip animation has started.

No Respite allows you to easily maintain your stamina for parrying, but can optionally be swapped for something else. Hubris is pretty strong since it has good uptime and applies to both toughness and health, but it can also be swapped if you want. Some useful alternatives: Zealous Pilgrim + Fire and Fury, Infectious Zeal, Anoint in Blood, Against the Odds, Wait in Line, Retaliatory Defence.

I recommend Zealous aura as a baseline for more potential parrying, pushing, blocking, and sprinting. Beacon of Purity is a good swap for missions with a lot of corruption, like The Blight Spreads and Pox Gas.

On the curios, you can swap the block efficiency perks for stamina regen, health, ability cooldown, or whatever else you prefer. I run stamina regen perks on most builds, but here I was able to take block efficiency instead thanks to No Respite and Zealous aura. The +3 stamina curio could optionally be swapped for toughness/health.

I like the Mk VII Devil's Claw best, but you can use a different variant if you prefer. I've included suggested attack combos below for each variant of the weapon. There's quite a bit of room for improvisation with the attack combos, especially when mixing in parries and push attacks.

Catachan Mk VII "Devil's Claw" Sword

• Cleave: heavy > light > repeat
  OR heavy > parry/block-cancel > repeat
• Single target: light > heavy > (light x2 > heavy > repeat)
  OR push-attack > light x2 > heavy > repeat
  OR light > repeat
• Monstrosity/boss aggro: parry when possible, then use light attacks between enemy attacks

Catachan Mk IV "Devil's Claw" Sword

• Cleave: light > heavy > repeat
  OR light > repeat
• Single target: heavy > light > repeat
  OR heavy > parry/block-cancel > repeat
• Monstrosity/boss aggro: parry when possible, then use single-target combo between enemy attacks

Catachan Mk I "Devil's Claw" Sword

• Cleave: heavy > repeat
• Single target: push-attack > light > heavy > repeat
  OR light x3 > heavy > repeat
  OR light > repeat
• Monstrosity/boss aggro: parry when possible, then use light attacks between enemy attacks