Weakspot Relic Blade
 Zealot Build - Warhammer 40k: Darktide 

We take Thy Wrath be Swift because the weapon is slow, and having stun immunity helps with it a lot especially with movement speed boost because relic blade doesn't have as much movement.

We take Munitorum Mk II Relic Blade because it has higher finesse multiplayer, compared to Munitorum Mk X Relic Blade (I prefer Mk X for the move set but the finesse mutliplier is 1.65x vs 0.66x)

On the relic blade we take Energy Leakage and Cranial Grounding with 25% unyielding (for boss damage with Purge the Unclean)and 10% melee weakspot damage and we can start stacking weakspot hits from 10% instead of 4% with Duellist it reaches very high damage boost to weakspots if you have the stacks so we can one shot enemies regular enemies and some maniacs with light spam and deal very high damage to bosses without needing to clear chaff for slaughterer to get activated. And also we we get to keep strenght stacks during our relic blade activation for longer time, yes you can take slaughterer to get bigger boost for horde clear but you mostly want to focus on activation damage  especially on single targets with this mark) With Stalwart we replenish a lot of toughness and get a lot of damage reduction to it as well. 

Works well up to Auric Maelstrome very well. (Haven't tested for Havoc yet)

Revolver for special sniping, dealing with snipers, gunners and nuking bosses that you can't reach. (I also prefer revolver because it gives me the mobility relic blade lacks, and more dodges)