General Martyrdom Zealot
 Zealot Build - Warhammer 40k: Darktide 

General Martyrdom Zealot build that I use. Pretty flexible in terms of blitz and ultimate. 

Weapon Choice

Munitorum Mk X Relic Blade is the best weapon for Zealot. Great damage, special activation gives even more damage and helps puncture through mauler and crusher hordes. Better than pretty much all other weapons of its type, though you can honestly use whatever weapon you like for martyrdom. We use Mk X because it has the better moveset imo. 

If you want to zoom and go faster, you can always pick up Combat Blade or Dueling Sword and give yourself carpal tunnel.

Locke Mk IIb Spearhead Boltgun is what I mainly use to magdump into problematic mixed hordes or into bosses. Cancel the weapon swap animation and reload animations using Blades of Faith.

Zarona Mk IIa Quickdraw Stub Revolver or Accatran MG Mk II Heavy Laspistol can be considered instead if you want to take out ranged specialists and aren't using blades of faith or aren't confident in your ability to hit blades.

Curios

I go all three +1 wounds curios, but you can technically swap one of them for a toughness curio and still maintain max stacks. Though with three wounds curios, you have much better synergy with Holy Revenant, as the max HP you restore with it will still maintain max martyrdom stacks with three wound curios, while it loses you a stack with only 2 wound curios. 

Revive speed is so mega important you should always have three of them. Three +12% ally revive speed and the Providence talent makes you pick up allies so fast, meaning they can get back in the fight quicker, you're less at risk of getting your rez canceled, and nets take like half a second to unnet someone. Best stat in the game imo.

At least 2 +20% damage resistance (gunners) is also mandatory. Gunner and reaper packs suck and they can shred through your toughness very fast. This is especially true in havocs where you don't get the toughness grace period, and they can immediately start shredding through your HP as well. 

I prefer combat ability regeneration so I can use my ultimates more, and you should consider more if you're using Chorus of Spiritual Fortitude to increase your uptime on it.

Other good curio perks are max health, toughness, and stamina regeneration (consider stamina regen especially on slower weapons like the relic blade we're using).

Until Death

There are two paths you can go with the subnodes for this keynode:

Holy Revenant only, allowing you 1-2 extra points to put into another node. This will be similar to the old patch, with some extra talent points to get you some nice nodes. However, you don't gain golden toughness nor burn stacks on weapon attacks. Your overall survivability (debatably) and damage goes down in exchange for the comfort of not having to stay at literally 1HP.

Zealous Pilgrim, meaning you also go for Risen and optionally Fire and Fury. With your martyrdom stacks giving you crazy attack speed, the amount of burn you can stack is crazy, but it might not be worth it depending on your melee weapon (I love it with Catachan Mk VI Combat Blade ngl wee carpal tunnel). If you don't want to, then you can pick one of the recommended swap nodes instead.

Blitz

I use Blades of Faith mainly for canceling the boltgun animations and for targeting distant specialists, but you can go stunstorm or immolation grenades instead if you don't want to do that. 

Stunstorm Grenade is better for clutches and "oh shit" moments more imo.

Immolation Grenade is fine but you already have good horde clear with relic blade, I don't think you really need more.

Ultimate Choice

Fury of the Faithful is just a general good feeling ultimate for toughness regen and damage, 2 charges can get you back up to full toughness immediately if you get your toughness broken. If you decide to take Zealous Pilgrim and its related subnodes (Risen and Fire and Fury ), you also gain a lot of unkillable uptime and therefore uptime on golden toughness and burn stacks. 

Shroudfield fills a similar purpose and can also have much better damage potential with backstabs, as well as clutches. You help contribute to boss damage a lot more with this ultimate. You can either forego Master-Crafted Shroudfield subnode or remove the Anoint in Blood node to take all three subnodes. Just be careful not to grief with it by aggroing a bunch of enemies and pressing the ultimate and making them all target your poor Psyker or something.

Chorus of Spiritual Fortitude is always a good support ability as well with Ecclesiarch's Call subnode. If you go Chorus, you can use the spare talent point for one of the recommended nodes.

Recommended Swap Nodes

If you have some spare talent points by going with certain choices as mentioned above, then you can take some of the following nodes instead depending on your playstyle:

Good Balance is consistent, good damage reduction if you're playing properly and dodging well.

Punish Impiety gives you more attack speed on push attack. Just good in general.

Anoint in Blood more ranged damage the closer you are to enemies. This is particularly good on the Locke Mk IIb Spearhead Boltgun or the Artemia Mk III Purgation Flamer, as they are mainly close ranged guns. The base ranged damage affects the flamer stacks funnily enough.

Restoring Faith for more survivability. I think if you're at 1HP and are in the unkillable state, it will actually heal you some more health funnily enough without having to rely on Holy Revenant.

Shield of Contempt grants more survivability to you and your allies. 60% damage reduction (not just toughness damage) is crazy.

Holy Tools this is only really for the Crucis Mk II Thunder Hammer tbh. I guess it's nice for dealing some meaty damage to bosses and crushers with a fully charged relic blade thrust.

Aura

Benediction for most cases and difficulties.

Beacon of Purity in very high havocs.

Cooldown Reduction Keystones

Pious Cut-Throat should almost always be up and gives you +75% CDR. Hitting heads with the relic blade shouldn't be much of a challenge, especially when you're cutting down hordes and hitting multiple poxwalkers at once.

Martyr's Purpose technically has 100% uptime, but scales based on missing HP and is only 50% CDR. Even if we're doing a martyrdom build, you're much better off taking Pious Cut-Throat here.

Invocation of Death is too inconsistent with this build as we're not going Blazing Piety nor are we using a high crit rate weapon, so ignore that here. If you decide to go with a different weapon with high crit rate, like a Combat Blade, then you can consider Invocation of Death.