Barbarian Battle Wizard (BBW)
 Psyker Build - Warhammer 40k: Darktide 

This is a Jack-of-all-Trades melee psyker focused on clearing hordes and Boss DPS

PLAYSTYLE/WEAPONS

You'll be using Covenant Mk VI Blaze Force Greatsword warp slash special to keep hordes under control. A fully charged warp slash will do enough damage to kill gunner elites and anything weaker. For the bigger enemies such as crushers and maulers, it will do respectable damage, but will mainly do high stagger, it'll even do enough to stagger a crusher in the middle of an overhead swing. 

We take Wrath and Riposte as our blessings. Since our base damage on the heavy 2 is already high we don't necessarily need any more damage and can instead take wrath to build up our warp slash faster. And Riposte is nice since the extra 20% crit for 6s on dodge raises our crit chance from 37.5%->57.5% while in scrier's gaze. 

You'll want to mainly focus on groups of elites since we'll be using Perilous Combustion to spread soul flame to nearby enemies (4-5m) perilous also has a nice interaction of being able to pass the "flame cap" of 16 and can instead reach 31, which is good for bosses as it lets you stack some extra damage. 

For our ranged weapon I chose the Equinox Mk III Voidblast Force Staff, We use this staff specifically for 2 reasons. First, the Alt fire is great for applying high amounts of stagger to enemies like raggers and even unshielded captains who are usually harder to deal with in groups. Second, this stagger is also great since teammates with "On Stagger" effects like skull crusher for mace weapons or arbities with Breaking Dissent can help pump up the damage numbers of you and them team

For our blessings on our staff I found Blazing Spirit and Rending Shockwave to be the best neutral game blessings. Blazing spirit will let us apply 4 Soulblaze stack on crit to a maximum of 6. The range that these DOTs can be applied is tied to ANY hit not just ones that do damage, meaning that the stagger radius can apply the DOT which is marginally bigger than the damage radius. the 4 soul blaze isn't usually gonna kill much other than groaners/walkers, but we take it to help activate Souldrinker and to give a slight bump to Perilous Combustion once we start killing elites. Next we take Rending Shockwave as Psyker doesn't have access to any other 40-brittle effects outside of uncanny strike on his melee weapon (which FGS can't get). This Talent is purely support for our Perilous soul blaze stacks and our team since Force GreatSword already has extremely high ADM values on it's heavies (roughly around 0.7-0.82 for the strike down and stab). If you want you can swap rending for any other blessing of your choice.

BLITZ:

I chose Brain Rupture and its Kinetic Flayer augment to get a free rupture every 12 seconds. This is great for 1 shotting all specialists except mutants or for stacking some extra chunky damage on bosses. If you want to go more support for the team you can instead go Smite with Charged Strike and Enfeeble, though it will cost an extra talent point to take both augments so you will have to sacrifice a talent point elsewhere

ABILITY:

for our ability we go with Scrier's Gaze as it provides the best benefits for a melee focused build. We take the augments Warp Speed to close distance faster and Precognition to add some extra finesse damage on top of the normal damage gained from scriers. Since a lot of psykers kit revolves around skimming on the edge of overloading for buffs, taking scriers to give us passive peril generation is our best way to activate those talents,

KEYSTONE:

For our keystone we take Disrupt Destiny Since it gives us some extremely strong stacking buffs and has some good survivability from the toughness regen and the movement speed it also provides. I took Lingering Influence over Perfectionism since the increased duration provided more benefits than 10 extra stacks. Something to keep in mind with Disrupt Destiny is that the duration is refreshed if you hit a boss, so don't feel rushed to kill a chaos spawn or plogryn if sitting on high disrupt stacks.

TOUGHNESS REGEN AND RESISTANCE:

As a melee psyker, you need to take extra precaution since you're the squishiest of the 5 current classes at 75 toughness and 150 HP. But thanks to our talent selections, we have enough regen and resistances to even give arbities a run for his dockets.

First with regen, we take Warp Expenditure, Quietude and Souldrinker (testing with souldrinker has concluded that the soul flamed enemy doesn't need to die from the DOT effect to proc, just that the enemy has soul flame applied when they are killed) as our talents, Scrier's Gaze for our ability, and Disrupt Destiny as our keystone. when all these buffs are active, we get a staggering 22.5% toughness regen/s for 2 seconds on a single kill With Quietude constantly giving an additional 4% every time we gain/quell 10% peril. granting nearly half our toughness in a single swing.

Next for Resistances, we take One with the Warp, and pair it with Scrier's Gaze's active 20% DR. we also take a mandatory 10% toughness DR minor node when traveling down the talent tree. All these stacked together (and at critical peril for one with the warp) results in a ~51.76% toughness DR. paired with our already absurd regen rate, allowing us to reliably regen back to full toughness before another melee attack can usually hit us.

CURIOS:

For curios we go for triple Toughness since it provides the best survivability and since psyker has the fastest stamina regen delay we don't need a stamina curio as long as we don't overextend with push spams or sprinting for too long. For the modifiers we got Revive Speed Since it's nice to have since faster revives means less time you can possibly get caught by disablers or overheads while reviving and 5% Toughness to add just that little extra bit of survivability. Finally, for our final perks I decided to NOT take the 4% ability CD since 12% reduction only reduced the cooldown of Scrier's gaze by 3s. which can easily be replenished by psykinetic's Aura. This leaves the 3rd perk on our curios as Personal preference perks, I personally took 3 +5% Health as in havoc 40 you only have 98 HP which is enough for Snipers to down you in 1 shot and bursters will leave you at around 5 HP.

ATTACK COMBOS:

the MK VI force great sword is a little more involved than the MK VIII, though still follows a similar attack pattern. Lights consist of a 4 hit combo of 3 vanguard diagonal's and a single strike down overhead. The heavy is 2 strike downs with an overhead chop and a thrust. and finally the push attack is a vanguard horizontal sweep. For hordes you can M1 spam and usually get out fine, though you can usually throw a few push attacks in to both reset enemy's actions and for a really wide sweep attack. For bosses you mainly want to make sure the Heavy thrust is the attack that lands as it does nearly double the damage that the overhead chop will do. (I can reliably land 11.5-12K weak spot crits against monstrosities in both the psykanum and in public games). Also keep in mind that the follow up light attack from either heavy attack will ALLWAYS be the strike down overhead, you can use this to kill weaker elites like shotgunners or gunners in a single headshot or to quickly dispatch a weakened elite such as raggers.