Victor's 'Havoc Reborn' Inferno Bubble
 Psyker Build - Warhammer 40k: Darktide 

The standard bread and butter build for Psykers, either this or mirror Reborn for Vampire and use Voidblast. As may toughness nodes as you can squeeze in while still getting all the effects you need, a bubble to hide within while burning everything down.

I ended up putting Warp Nexus on this as while it makes it more annoying to spam it's secondary fire, since you don't have Shriek you need those crits to get your flame stacking quickly. Not to mention the crits keep your speed and toughness up even further, so it's important to have regardless of how much I enjoy keeping Blaze Away up cleaner with Warp Flurry. 

Other than that, just spam bubbles on cooldown, burn everything in your path, and use your greatsword for spacing and to drop armor if ever you happen to need to, as well as to block bullets in a pinch. Stay behind your squad, drop everything in fire, keep everyone standing while funding all their abilities including your own. You are an ability and toughness battery on top of wave clear, and you do it all VERY well.