Flexible Greatsword Psycher
 Psyker Build - Warhammer 40k: Darktide 

Very flexible melee Psycher build. Pretty easy to play and a decent all-rounder. It should work from early to Havoc.

You swing the Greatsword in melee and shoot ranged targets with the Laspistol. Pretty simple.

I prefer to use Covenant Mk VI Blaze Force Greatsword because of its incredible Heavy Attack range and damage. It also has a very easy moveset.

Spam Light Attacks for hordes or if you want to move around.

Use Heavy Attacks for anything else, like shield guys, Elites, Crushers, Maulers, and bosses, for sure. Heavy Attacks hit hard enough that hitting the weak spot will most likely one- or two-tap everything.

Try to focus on Disrupt Destiny marked targets first, if possible. Shoot them with the Laspistol if they are far away. Thanks to Kinetic Flayer, you can do this pretty easily.

If you don't feel comfortable keeping your Disrupt Destiny stacks, you can go for Lingering Influence instead of Perfectionism, but it's not recommended.

Keep your Greatsword Special for giant hordes or packs of Elites/Crushers/Maulers. Be careful: you can explode yourself with the Greatsword Special if you're at 100% Peril without Warp Unbound (which we do not take), so keep an eye on that. Quell for half a second, then use the Special.

Try to keep Scrier's Gaze up all the time for damage and mobility. You can prolong it with By Crack of Bone or simply by quelling during safe moments. 

Shoot ranged targets with the Laspistol, or use it to land crits and refresh your ranged dodge immunity with Empathic Evasion.

The Laspistol deals amazing damage to anything except Carapace-armored targets. So, if needed, you can just run around and shoot.

I prefer to avoid using Brain Rupture at all. It's much easier and safer to shoot ranged targets or even run into melee.

Perilous Combustion is a very good talent for increasing overall damage, since you're supposed to kill a lot of Elite enemies and it can proc Kinetic Flayer.

Malefic Momentum increases the Warp damage of Kinetic Flayer and Perilous Combustion. They can also boost non-Warp damage.

You can exchange Malefic Momentum for Warp Splitting to increase cleave damage, Immaterial Focus / Just a Dream for survivability, or Tranquility Through Slaughter if you want to keep Scrier's Gaze up longer from range.

The build does not include Warp Expenditure because its second effect is too weak for the Greatsword's attack speed, and there's already enough Toughness recovery from other talents.

Gear:

• You can grab any Laspistol (or any Recon Lasgun), but I prefer Accatran MG Mk II Heavy Laspistol more.
• Two Toughness curios are kind of necessary.
• Health curios can be changed for anything you like. I prefer the extra HP for survivability. You can go for Stamina or more Toughness instead.
• Gunner resistance is also flexible. I prefer it because it makes running from target to target safer.
• Why not use any staffs? You can't shoot them at 100% Peril. Laspistols are incredibly strong with crits (Infernus) and let you run around like crazy with Warp Speed.

Pros:

• All-rounder;
• Easy enough to learn and play;
• No melee combos, so you can concentrate on the game;
• Extremely long melee range, so you're almost always at a safe distance;
• Great horde clear and boss damage;
• Amazing damage against Elites, Crushers, and Scab Maulers;
• Decent survivability;
• Amazing mobility with Warp Speed and the Laspistol;
• Immunity to ranged attacks most of the time because of Empathic Evasion (and Anticipation, if taken);
• Kinetic Flayer works in melee and at range, so you can one-tap almost anything even with single shot of the Laspistol;
• Almost completely safe Peril gameplay, so you're basically safe from exploding yourself.

Cons:

• Selfish. No team support or CC, only damage;
• You need to prioritize marked targets, but it's not strictly necessary;
• You can explode yourself with the Greatsword Special if you're at 100% Peril without Warp Unbound;
• You can't quell with the Laspistol;
• Requires some ammo to shoot;
• You still need to press buttons.