The BEST Psyker Build | Rat's Trauma Psyker
 Psyker Build - Warhammer 40k: Darktide 

Squeak! (To preface, Rat would highly recommend watching Rat's gameplay on Twitch at TheRatOCE to learn how to scurry with this build. Rat is happy to answer any questions in chat.)

Introduction

With this build, you will be able to handle anything from Auric to Havoc 40. It is difficult to learn how to use the Trauma Staff in tandem with the duelling sword at it's full potential. But if you have mastered it, then you will be able to singlehandedly carry any game in any situation.

The Trauma Staff

The Trauma Staff is the single best weapon in the game. It is ranged with no ammo, has incredible stagger, and when paired with animation cancelling and rat-like move tech, allows you to deal with every threat, short of bosses, that the game can throw at you. Your impact on the battlefield is wide and far reaching thanks to the staff's range. You can stagger and suppress specials, elites and ranged enemies. You can support frens being overrun by ragers from a distance. You can stop a hoard of crushers dead with the staff's stagger. You can push through a hoard of elites or out of a corner by moving forward and trauma blasting at your feet. You can even use the staff as utility, popping all 3 corruptor growths to reveal the Daemonic Corruptor in under 3 seconds, making it so that you can strike out on your own on events like the end of smelter complex and singlehandedly clear 1 or 2 Corruptors by yourself.

Rat cannot overstate how powerful the Trauma Staff is.

Animation Cancelling with the Trauma Staff

Rat's build emphasises the Trauma Staff as the main weapon with the duelling sword as a supporting weapon to kill/finish priority enemies. 

If you were to play Trauma Psyker traditionally, the main drawbacks of the staff is its long recharge time after each secondary attack and how slow you move while using the staff. Luckily, both these shortcomings can be solved with rat tech. To scurry like Rat with this build, by far the most important skills are to learn animation cancelling with the staff which allows you to spam secondary attacks, and eventually incorporate slides and peril quells into the animation cancel input rotation to regain your mobility and manage peril. 

Basic Rat Tech

In the most basic form, the animation cancel inputs are: 

1. Secondary staff attack
2. 1 to switch to melee
3. 2 to switch to staff
4. Repeat.

Rat does this when movement and dodging isnt necessary or when holding a position from a safe vantage.

Intermediate Rat Tech

A more complex input rotation is: 

1. Secondary staff attack
2. '1' to switch to melee
3. '2' to switch to staff
4. 'R' for a short quell
5. Repeat.

Rat incorporates 'R' into 100% of input cycles as it is key for sustaining the sheer amount of attacks Rat spams.

Advanced Rat Tech

Finally once you have mastered that, it is time to incorporate sliding into your rotation. This can be done by:

1. Secondary staff attack
2. '1' to switch to melee
3. Shift to sprint forward
4. Slide pinkey down from Shift to Ctrl to slide forward (sliding with the duelling sword is key as it has a higher mobility stat and thus your slides go further)
5. '2' to switch to staff mid slide and charge secondary staff attack
6. Repeat.

This rat tech is by far the hardest to learn, but is THE MOST IMPORTANT and commonly used by Rat. Sliding does multiple things:

• Provides mobility in an animation which otherwise would slow you down
• Allows you to kite hoards while spamming secondaries
• And gives invulnerability frames from ranged (NOT MELEE... crushers hurt ;~;)

Notes and tips:

• Spamming secondary attacks can only be done efficiently once you have 3 stacks of warp flurry which speeds up staff secondary charge speed.
• Rat rarely fully charges the secondary attack as Rat can spam faster with smaller charges (usually sticking to 50%-90% charges). Full charges should be used when going for certain breakpoints or trying to focus down specific enemie(s).
• Rat would strongly recommend not being indecisive and holding a 100% charge for longer than absolutely necessary, as it really reduces your dps (get in the habit of just flicking towards the nearest enemy).
• Rat has Blast Radius as the dump stat on the staff as being able to spam secondaries more than makes up for a reduced blast radius.
• When possible, stagger enemies towards yourself or your frens to make it easier to melee them and/or hit their heads.
• Prioritise ranged enemies when possible (especially important in high havoc).
• Hounds are very susceptible to stagger, so make sure to push them towards you with staff secondaries for a poke.
• When possible, find high ground as it increases your range, makes aiming easier, and allows you to keep better track of threats, especially specials and ranged.
• Rat has Jump binded to Alt to prevent accidental jumps whilst spamming dodge. (SUPER IMPORTANT)

Move Tech with the Trauma Staff

The second most important skill with the Trauma Psyker is good movement. You can stagger everything by spamming secondary attacks but enemies will still advance on you, and walking backwards simply won't cut it. This is were it gets more difficult and more traditional skills such as aiming, positioning and your ability to react on the fly will be tested. 

In short, the best way to kite is to slide away after every secondary attack, similar to the aformentioned Advanced Rat Tech. However the key difference is that instead of sliding forward, you must turn 180 degrees before sliding away from the enemies. It will sound something like this:

1. Secondary staff attack
2. '1' to switch to melee
3. Turn 180 degrees or in the direction you want to go
4. Shift to sprint forward
5. Slide pinkey down from Shift to Ctrl to slide forward
6. '2' to switch to staff mid slide and charge secondary staff attack
7. Turn back to face the enemy
8. Repeat.

Move tech with the Duelling Sword

There is plenty of resources online regarding this so Rat will stick to move tech for this build specifically.

A major skill which players usually neglect is learning how to chain slides properly with the duelling sword. The heaving attack on the duelling sword gives a short burst of speed. This can be used when chaining slides to significantly increase your speed and maintain momentum during slide chains. The inputs are as follows:

1. Charge a heavy attack with the duelling sword while running forward pressing Shift
2. Slide pinky down from Shift to Ctrl to slide forward (then hold Shift again immediately after the slide)
3. Towards the end of slide as you begin to lose momentum, release your heavy attack
4. At the end of the speed boost received from the heavy attack, repeat steps again

Note:

• It is fine to have a brief period between the heavy attack and slide where you are running forward.
• If you do this properly, you will notice that you in fact GAIN STAMINA doing (which is why learning this skill is so important as it reduces stamina consumption while roaming and during fights)
• When you slide, you are locked in that direction until the end of the slide, so plan your movements accordingly.

Ledge Dashing

Dodging to the side off a height allows you to maintain your dodge momentum until you hit the ground. This skill is extremely important and helps you maintain even more distance when kiting, or scurry faster to save your frens during a clutch situation. Again there is a lot of info online about this which explains it better, but practice this skill wherever you can and you will truly scurry like a rat. ;D

The Duelling Sword

The duelling sword is never used to clear hoards, it pales in comparison to the staff. Instead, it should only be used for its strength which is poking heads.

There is not much to be said for the duelling sword apart from the fact that it finishes off enemies and acts as your primary source of damage against bosses. How you incorporate the duelling sword into your trauma psyker playstyle comes down to individual preference but Rat can give some tips on some things that Rat usually does.

• Be familiar with secondary attacking with staff, quickly switching to melee for a single heavy stab, and back to the staff for more secondary spamming.
• A secondary staff attack (~75-100% charge) and a head poke with the sword is usually enough to kill most specials and elites (short of tankier ones such as crushers, muties etc). Rat makes sure that those enemies are staggered/thrown forward towards Rat so that they are closer and their head is right in front of Rat for a poke :3
• Muties usually die from 2 face pokes, so learn how to poke their face as they are charging towards you, then dodge sideways and poke their face again from the side. It is by far the fastest way to kill them and allows you to get back to staggering the hoard asap.
• The secondary attack on the duelling sword can be helpful for staggering larger enemies such as crushers and maulers.
• Learn the attack pattens of bosses, and how to get them into attack animation loops (more information regarding that can be easily found online). From that point on just poke their heads :3

Skill Tree

Form follows function. The importance of quick Trauma secondaries dictated the direction of the skill tree. Three -5% peril generation modifiers, Battle Meditation (10% chance to quell 10% peril on kill), Solidity (Increases quell speed by 30%), Empyric Resolve (-40% peril generation. -30% toughness replenished) and Inner Tranquility (-6% peril generation for each Warp Charge) all facilitate Rat's spammy Trauma playstyle. 

Going top to bottom from the skill tree:

• Perilous Combustion is useful especially on higher difficulties due to the amount of specials and elites. It helps in mixed hoard clearing and is generally nice to have, however it can be changed for other nodes if you have different personal preferences.
• Brain Burst is chosen only for the -5% peril generation modifier, but can be helpful when dealing with far away snipers or ranged where the Trauma Staff can't reach. However Rat would advise to use this as little as possible as it is simply not worth your time. 
• Bubble is by far the best talent for this playstyle as it allows Rat to push aggressively when needed, and shield to restabilise and create space. As well as being important for setting up in rat holes (spots which break AI) which Rat is fond of finding and testing (or any position which you need to defend for that matter).
• Crystalline Will (You can pop but won't down) may be controversial but Rat finds that Rat pops around once a scurry. And often when that happens, it is during a high intesity situation where if Rat dies, the team will soon follow. 
• Kinentic Deflection (Blocking causes you to gain Peril instead of lose stamina) is extremely important for survivability against bosses, and for reviving downed frens.

Notes:

• If there is a psyker on your team who will proc Soulblaze often, it may be worth switching Psychic Vampire for In Fire Reborn (keystone modifiers)
• If Rat is speedrunning or playing easier difficulties, Rat might swap Psychic Vampire for the +5% movement speed modifier. 

Curios

• Rat takes 1 wound Curio as Rat tends to blow up >.< (Rat favours consistency over maintaining perfect play 24/7 because eventually, you WILL make a mistake. And because of how strong you are in any team, you're death will have far more of an impact on the success of a scurry than any toughness or health Curio.)
• Having 60% Resistance to Gunner damage is important to Rat's aggressive playstyle and helps immensely (especially in high havoc) when dealing with ranged.
• Combat ability regeneration can be switched for corruption resistance for The Blight Spreads havoc missions, or Max Health (or whatever your preference is)

Squeak! (Until now, Rat has not seen a single person scurry as well or better than Rat using the Trauma Staff, perhaps because not enough people recognise the strength of the weapon, or because the tech has not been discovered by the vast majority of players. Rat sincerly hopes this guide helps you and would love to see people's progress and eventual mastery of rat tech in the future.

Thank you very much for reading and Rat hopes our scurries cross paths eventually)

Squeak! :D

(Video demonstrating gameplay below)