John Greatsword
 Psyker Build - Warhammer 40k: Darktide 

Strengths:

• Big weak spot & crit damage
• Horde clearing (Greatsword cleave and special attack)
• Great mobility and evasiveness (Warp Speed + Disrupt Destiny & Anticipation)
• High toughness regeneration
• Greatsword Mk VI and VIII both viable, pick whichever suits you:
  • Mk VI for extra single target damage output (H2 deals more damage).
  • Mk VIII for ease of use (but still strong!), simpler attack patterns brings more consistency.
  • Hold primary attack when doing a 'push' to inflict big stagger on a single target (has long reach too), I use this mostly against Pox Bursters (this triggers them too), Crushers, and Bulwarks. Release block immediately after this while still holding primary attack to do a follow-up heavy (BIG damage with Mk VIII).
• Voidstrike and Voidblast staff both viable, same primary fire is good on its own for sniping, as for secondary fire:
  • Voidstrike if you prefer big damage against single target and clearing tightly lined up groups, big stagger against Crushers and even Beast of Nurgle when hitting their face at full charge, for Bulwarks you only need to full charge their shield and they're cooked.
  • Voidblast if you prefer more crowd control and brittleness debuff utility (with 'Rending Shockwave' blessing), though greatsword can already do a lot against hordes. Be wary that compared Voidstrike, enemies staggered by Voidblast are immune against the same stagger for a longer time.

One of the trickiest obstacles to face with this build are groups of ragers, greatsword has longer reach than them, but they are annoying to deal with when they are mixed in with hordes.