Warhammer 40,000: Darktide – How Psyker Brain Knives (Assail) Works

A quick guide for the funny projectiles.


I thought I would put together a quick guide explaining how Psyker’s Assail works, since there isn’t much explanation in-game.


There are two fire modes for the ability, untargeted (primary fire) and targeted (alternate fire). I’ll discuss primary fire first.

Primary Fire

When using primary fire, you toss a shard that bounces around chaotically in roughly the direction you threw it. This costs ~10% peril. The direction they’re thrown has some inaccuracy but they will wiggle around on a fairly straight path.

If a shard hits a hard surface, it will bounce off and continue flying on a new path. This can happen several times.

If you are looking at an enemy, any shards within a fairly large radius of that enemy will home in on it and hit it. Each shard will only hit a specific enemy once, if you want to damage an enemy multiple times, you need to throw multiple shards.

Any enemy that’s near your crosshair (essentially a small circle around it) will be targeted by nearby shards. You need to have line of sight to the enemy for shards to target it. They prioritize enemies closer to your crosshair rather than those closer to the projectile itself.

Shards aim for the head but they don’t always hit it. You’ll have slightly better luck if you aim a bit high when throwing them.

Also, you don’t need to have your blitz equipped to control the shards.

Secondary Fire

When using alternate fire, you lock onto an enemy in your crosshairs. You have to be aiming directly at them to get a lock, although it won’t be broken if you look away or break line of sight. This means you can bend shots around corners or over enemies if you want.

Throwing a shard with the alt fire costs more peril (~25%) but it travels faster and straighter than primary fire, and homes in very aggressively. It will continue to try to hit the target until it succeeds or flies for too long. It continues tracking even if it bounces, and ignores other enemies.

Once an alt-fired shard hits its target, it behaves like a primary-fired shard and will hit enemies near your crosshair.

Projectile Damage and Properties

Shards do good damage to all health types except carapace (and are a bit worse against unyielding).

Shards are a projectile and are affected by limb damage modifiers, meaning on most enemies, they do half damage to arms and legs (compared to body-shots).

Shards can crit. This is per-shard rather than per-hit, so you can have a single crit shard mow down half a horde. That also only counts as one crit.

Shards have a limited amount of “cleave” that is affected by what they hit. They have better cleave when they crit. This can also be improved with one of their sub-talents.
Hitting carapace breaks them instantly.

Shards count as ranged attacks and as warp damage. This means you can get guaranteed crits from the “True Aim” talent.


Shards count as ranged attacks, count as warp damage, can hit headshots, and can crit. This means they have a LOT of interactions with talents.

These talents care about ranged attacks:

  • True Aim

These talents care about warp damage:

  • Soulstealer
  • Perfect Timing
  • Malefic Momentum

These talents care about headshots:

  • Precognition (Scrier’s Gaze)
  • True Aim
  • Cruel Fortune (Disrupt Destiny)

These talents care about crits:

  • Mettle
  • Perfect Timing
  • Prescience
  • Empathic Evasion
  • Scrier’s Gaze
  • True Aim
  • Disrupt Destiny

“True Aim” in particular is quite strong with Assail since it can both build stacks for the crit, and trigger it.

Originally posted by HalibutHD

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