Sashimi Zealot
 Zealot Build - Warhammer 40k: Darktide 

Build Info

Pros: 

• One-shot muties with a strikedown heavy weakspot hit without buffs or a bodyshot with buffs up
  • Tear through the "waves of muties" maelstrom condition with ease
• Some of the best horde-clear in the game, great for when you're paired with only psykers and vets.
• Give groups of ragers the quick death they don't deserve but by the Emperor's mercy. 
• You are extremely useful in pretty much any situation the game throws at you

Cons: 

• Low melee boss damage
  • Low boss damage in general if using revolver
• Can't quickly deal with distant gunners and specialists if using bolter
• Reliant on ranged and blitz for carapace

Strategy

• In a horde, try to clear trash off your teammates. Killing enemies from behind will quickly charge up your ability. Use a heavy every once in a while if you need toughness.
• Against Armor, Alternate between Heavy 1 and your Special, the special has very high stagger (but not enough to stagger a crusher anymore)
• Dodge often to keep up momentum stacks. 
• There's only a little wiggle room for the damage breakpoint in 1-shotting Muties.
• Use your speed to clear flanks as you move forward so that your backline can do their jobs untroubled. If you don't then all the trash you left behind will go attack them in addition to specialists and whatever else spawns behind the team. When that happens you get no support up front.

Heavy Sword Marks

VI has a single target first heavy and hordeclear second heavy, lights can potentially do good horde damage. Alternating the single target heavy and the special attack is good against lone ragers. Rampage is a good alternative to deathblow if you want to use the lights. 

VII is pretty much the same as VI except the heavies are reversed, making it slightly better at mixed hordeclear since you can alternate the wide attack heavy with the special attack. 

IX has an initial single target heavy, but chains into endless hordeclear heavies. The versatility of always being able to chain into a powerful single target or powerful horde-clear combo generally makes it the best option. 

Alternatives

• Blades of Faith route is good and lets you be more flexible against specialists. 
• The blessing Rampage is almost as good as Deathblow on the mk VI, as the power buff adds enough cleave to kill 2 poxwalkers with each light attack and makes it easier for a single heavy to kill ragers.
• Pinning Fire is nice on the Bolter over the bleed, but doesn't help nearly as much against monstrosities or groups of Crushers unless you stagger something first and that's not always an option. 
• Zarona Revolver is a great choice for this build as well. Not as strong against monstrosities or large groups of armor, but you can deal with specialists and gunners much more easily. 
  • Surgical, Hand Cannon, Flak, Carapace
• You can swap out Momentum for Martyrdom if you want, it's useful but not as consistent. 
• Instead of Thy Wrath Be Swift, you can take Punishment and whatever else with it.