Relic blade/Boltgun DD Zealot
 Zealot Build - Warhammer 40k: Darktide 

Based on this pre-update (Bound by Duty) build by Johan, I tried my best recreating and adapting it to the current tree:  https://darktide.gameslantern.com/builds/9da39b45-5a0a-4ed1-9b0e-670f8ad96e33/perfected-relic-warrior-with-explanation-and-tips

Notes:

• Fury of the Faithfull is mostly used off CD during combat (as it's essential to keep the sword's attack speed high enough) - or as gap closer
• Revive Speed (Ally) perks on curios can be swapped for full stack of +Toughness perks if more survivability is needed; RS(A) synergizes nicely with Providence though, allowing you to save/revive allies super-fast
• Consider moving point from Duelist to Shield of Contempt for extra survivability if you need it (there are tons of damage resistance and toughness regen in this build beyond that, but still)
• Note the Backstabber talent; don't stress over it, but if you see an easy way to dodge-flank something beefy for those sweet extra 25% damage - sure, do it (bosses including); it also helps to "average out" your damage in cases when fighting in the middle of a hoard, when you often hit mobs from behind or flanks naturally and it's not that easy to hit heads as from the front; if proved irrelevant for your playstyle, take something else instead
• Use Boltgun sparingly, to remove priority range threats and specialists - as well as for extra burst damage when it spirals out of control

Text below is provided "as-is", as originally written by Johan.

After 600h of Darktide, and lot of testing with the relic blade, here what I think is the most optimal build to play with it.

The build depend on three things : CRITs, dodges and Fury of the faithful

CRITs : 5% base + 15% blazing piety +30 % scourge = 50% CRIT chance that will be active most of the time  

With this "Enduring Faith" will give a permanent +50% Toughness damage reduction, making you the tankiest class in the game (sorry ogryns)

Dodges :

It gives you : +50% damage boost to weak-spots and CRITs, 15% toughness back and +25% Toughness damage reduction.

With this you are not dependent on other to survive if things go south or you need charge ahead to eliminate threats to the team.

Fury of the faithful : 

Is here boost your damage, restore your toughness, but most of all boost your attack speed by +20%!!!  

You will do so much CRITs that it will be recharged by the end of its effect thanks to "invocation of death", with an additional charge just in case. 

It s a must have for the relic blade since it is slow by itself, always use it when in melee.

Munitorum Mk X Relic Blade

+ : excellent horde clear, very good elite damage, incredibly fun to use

- : Combos need to be learned to use effectively, slow heavy attack, low mobility

To kill an elite : 'heavy + heavy + light attack' and repeat with 'heavy + heavy + light attack'

To clear an horde : 'light + light + heavy + heavy ' then continue doing heavy attacks until everyone is dead (it will continue the chain)

Boltgun

Your answer to a squad of crushers/maulers or bosses.

While changing weapon, throw a dagger to be able to instantly fire. Once you have decimated/thinned the enemies, don't be shy and finish in melee. Reloading is long and you will be vulnerable while doing it. 

Bosses melt under its barrage.

It can also be good for long range if needed, but this will be rare.

"Mobility" is the dump stat and should be at 60%.

Tips :

- If cornered, continue to dodge even if you are blocked by the crowd, you will be surprised how the generous the window of dodge is and that the distance of it doesn't impact the bonus our build give if successful.

- Blades of faith : aim a little higher to do head-shots, it takes practice, but the reward is fantastic, I no longer miss the immolation grenade that was a staple for me for a long time. Perfect for snipers as it kills them even with body shots.

- don't dodge the dogs, block and push and kill them in melee.

- max your character height, it facilitate aiming for the heads on enemies with melee.

- sliding count as a dodge ! Always slide when charging or escaping if you don't use your ability.