EASIEST MELEE + GUN Psyker Build | GUARANTEED Success!
 Psyker Build - Warhammer 40k: Darktide 

Easy, high damage, tanky melee gunker build.

PLAYSTYLE

Psyker's Force Greatsword VI (FGS) is one of the best weapons in the game. Great at both horde clear and single target, also easy to use. You should be in MELEE 90% of the time, FRONTLINING for the team, the other 10% you should be regrouping with your team during bulwark/crusher waves and boss spawns. This is NOT a ranged build, you should ONLY pull out your gun to kill SNIPERS, far away REAPERS and GUNNER packs, or get chip damage onto RAGERS and BOSSES before they come into melee range. You should NOT need ammo packs, even in high havocs without a veteran you shouldn't need more than 1-2 large ones. Always go for WEAKSPOTS, always be SLIDE DODGING, and try to use your sword. 

The goal is to be high peril all the time, taking the Warp Ghost talent to greatly reduce peril decay. Why? To take advantage of Unstable Power on the FGS (bugged tooltip, it's actually up to 20% strength), and the Warp Rider talent. Since you don't have assail or a staff, you build peril by: taking damage (through Just a Dream), Scrier's Gaze, or FGS Warp Slice special attack (you can also take kinetic deflection, personally I prefer just using stamina). Don't worry about peril, as long as you are using Scrier's and charged warp slices, you'll almost always be at least 50% peril. It's practically impossible to explode since you can only do that by warp slicing at critical peril without Scrier's. Use warp slice to maintain peril during downtime.

Psyker in the FRONTLINE?? Yes, if you take all 5 nodes below your auras (3 tank, 2 QoL nodes), Psyker's basically a tank. As long as you are below 97% peril, Just a Dream gives you a flat 25% damage reduction all the time. When you are at critical peril, you have One with the Warp at max benefit giving you 33% toughness damage reduction. Do you NEED all 5 of them? NO, just taking 'Just a Dream' + Anticipation is enough, but honestly it's hard to meaningfully increase your damage by much at this point, so you might as well take all of them. At most you can do 'Perfectionism' + 'Cruel Fortune' in high havocs, dropping Lingering Influence, and either Emphatic Evasion or Immaterial Focus.

Why not take 'By Crack of Bone' to be in Scrier's as long as possible??? First, it costs an extra point. And in return for a longer Scrier's, you become SIGNIFICANTLY weaker whenever it is NOT ACTIVE (not talking about the lingering effect). This is because if you're fighting, BCOB + using Scrier's will constantly tank your peril and make it stay there, nullifying all your high peril buffs, and giving you lower average peril throughout the game. Basically, BCOB is a tradeoff, for the cost of a talent point you'll get higher highs but lower lows, which IMO isn't worth it.

Why no ASSAIL??? Yes, if you're tryna be a sweat maximizing every last drop of damage, Assail weaving + Malefic Momentum is a thing you can do. However, Assail is bad in this build because you have Warp Ghost and no BCOB. You can't spam it enough to make Malefic Momentum worth it when your peril is always high. The whole point is to SIMPLIFY, stay at high peril, use your sword, unless you need your gun. Assail overall, while fun, is redundant since anything it can kill, your sword or gun can kill faster. Brain burst is taken instead for kinetic flayer, I find that it increases overall damage by 5-10%, and considering this only procs on priority targets, that's pretty dang good.

WHY NO SMITE + CHARGED STRIKE??? Smite doesn't do enough damage nor last any meaningful amount of time unless you go all out on a smite build. It's basically useless, but so is brain burst, so whatever. Charged strike only procs on heavies and does pitiful damage throughout the game.

HORDE CLEAR COMBOS

• TRY HARD (or macro): L1 -> L2 -> (optional L3) -> Weapon swap -> REPEAT
  • Not recommended for normal people
• L1 -> L2 -> (optional L3) -> Block cancel (tap block) -> repeat
• Light spam
• (my preferred) PUSH -> light attack -> light spam
  • I like starting with push since it gives you safety in hoards. With FGS, after you push, if you light attack (NOT push attack, which for the FGS is a garbage single target push that's only good vs bulwarks) you get this nice horizontal sweep attack for some reason, which chains into light spam. Idk why this isn't mentioned anywhere in the game. The main thing about this is sometimes you block instead of push (which is fine), or you accidentally push attack, which is highly annoying, so try to avoid that.
• Warp slice (at max stacks, does significantly more damage)
  • Try to use it BEFORE activating Scrier's gaze

SINGLE Target COMBOS

• Heavy spam (h1 -> h2)
  • Really try to aim for the head vs carapace (and in general), FGS has great finesse and crit scaling.

WEAPON PERKS, BLESSING, CURIOS ALTERNATIVES

• FGS: Dump warp resistance. Unstable power + Shred due to always being consistently active.
  • Wrath feels nice, but doesn't help you vs carapace
  • Any buff requiring you to dodge is mid af. As such, Riposte is only ok due to lasting 6 seconds, but still up less often than you think. Precog lasting only 2 seconds makes it terrible
• RANGED: Personal choice between the recon lasgun and the laspistol
• CURIOS: Personal choice. I recommend at least one revive curios for good luck.
  • In havocs, have > 100 HP to survive bursters (at minimum a single 5% health)
  • In havocs, consider gunner resistance curios, since they'll randomly spawn and kill you out of nowhere. 3x curios will reduce damage by half, which tbh doesn't do shit, so I'd rather have the toughness, hp, and cdr. PAY ATTENTION and always be slide dodging.