Leh Charge Zealot Xev
 Zealot Build - Warhammer 40k: Darktide 

Crusher or Maulers just charge (ult)  heavy attack in to block attack spam, if no stam just heavy attack twice and back to block attack spam (yes you dodge left or right aswell and if the buff goes away re charge)

Against Ragers Charge into a pack of em and dash left to right while spamming block attack, If they get out of the stun charge back into em and you should be able to kill a pack of em. If you do not have any charge and a pack shows up hold block until they start doing their attack animation and dash back and mag dump into em or spam your knives at the head.

Horde spam left click and the occasional block push. Charge when you do not have any Scourge and there is like a weird interaction where you charge into a horde and sometimes it gets you stuck in some trash mobs and for some reason you killing those guys gives back stab cd somehow.

Bosses um charge heavy attack in to block attack spam.

Beast of nurgle wait for animation for it to spit to you then charge to its sides and charge heavy attack into spam block attack, If it hits you away or stuns you when your doing block attack spam, then charge heavy attack and spam block attack, usually a weakened beast of nurgle dies in 2 cycles of your ult if you are not interrupted by any special enemies like trapper or hound

if until death and holy revenant is down then play safe 

Important stats for knife is  First target, Finesse, Pen and Damage. Mobility can be at 60% and you will be ok

if you want more crit drop second wind or swift certainty or pious cut-throat  

Edit: I now run only one ult charge and have the extra node for bot right of the ultimate