Martyrdom Zealot (Bound by Duty)
 Zealot Build - Warhammer 40k: Darktide 

Just dont get hit twice.

Bound by Duty Update: The new Godwyn-Branx Mk VI Bolt Pistol has slightly less damage for a significantly larger explosion AoE, I don't think the damage makes a difference especially with +Flak Armor and +Maniac But, the massive AoE buff lets you clear out hordes from a distance

General Build Info: PlayingMartyrdommeans should be playing at as low health as you can maintain to max out the buffs you get. The safest ways to take damage is from barrels, as long as you position yourself so they wont knock you off the map. Fire barrels can get you however low you want, normally I stop at 3 wounds or so. Getting grabbed by a Mutantis also very consistent, but only rely on them when they're the only ones around, or you have both charges of Fury of the Faithful to get your toughness back.

Fury of the Faithful is your most reliable way of getting your toughness back, generally you should try to save one charge to use right after you get hit, but you also want to use it right before it reaches two charges, the attack speed is extremely useful for horde clear and the initial attack is wonderful for taking out anything.

You will inevitably take damage, andUntil Death and Holy Revenant together are there to keep you alive and give you time to get your toughness back and get out of that situation. You should heal if you get corrupted or if you have around 10 hp or less, but dont be too brave, if you're too low or badly corrupted, just heal, its not too hard to take damage. The most common reason you'll get too low is if Until Death triggers, but you cant heal up with Holy Revenant. Normally its worth it to throw yourself into danger or switch to your secondary to shoot at anything you can, and you need to actually do damage to heal, just damaging the miniboss Scab Captain void shield's arent enough. When Until Death is on cooldown try to stay back a little more and pick things off from range instead of risking dying off in the middle of a pack of enemies.

Weapons: Indignatus Mk IVe Crusher IMO the best option for Martyrdom builds, its unique special attack is a shockwave that lets you play extremely defensively. Its special light attacks deal more stagger, and special heavy attacks deal more damage, its main combos are; All light attacks for horde clear, repeated special light 1 attacks for crowd control and pushing things off of you and your team, and special heavy 1 light 2 for damage. For Bulwark use special light 1 to knock back their shield and stagger them, then light 2 and heavy 1 to finish them off, you arent able to finish them off in one combo anymore, but you can stagger whole groups of them with your charged light 1 attacks. It does have difficulty with Dreg Rager and Mutant but ragers you can knock down with special light attacks. If you really want you can switch out one of the perks for +Mutant damage, but generally i find it more useful to have an easier time withCrusher Scab Rager andInfected Moebian 21st 

Secondary:Godwyn-Branx Mk IV Bolt Pistol i prefer it over the Locke Mk IIb Spearhead Boltgun due to the much faster swap speed, it is very doable to use a charged light attack to knock back a horde, then quickly switch and take out a specialist before switching back. Either version of the bolt pistol is fine, the new Godwyn-Branx Mk VI Bolt Pistol has less damage but more aoe so its better with Lethal Proximity which also buffs your Indignatus Mk IVe Crusher special attacks. The revolvers are a good alternative if you prefer those, but being able to help deal with hordes andCrusher from range is very nice.

Curios: The last slot on each curio is variable between +Toughness, +Gunner Damage Resistance, and +Health. +Toughness is obviously the default, +Gunner Damage Resistance is very good for havoc, even if you're good at sliding, but +Health gives you a bigger health buffer to work with so its also a good choice.

For teams, your best friends are anyone who can give you gold toughness, Vetrans withVoice of Command and other Zealots withChorus of Spiritual Fortitude. At your full 5 stacks of I Shall Not Fall you have an extra 37.5% toughness damage reduction, normally you have to avoid getting hit more than twice in a row, but any bit of gold toughness gives you a massive buffer to work with. Unfortunately you really need Fury of the Faithfuljust for toughness replenishment, so you cant really take it yourself