Ultimate Lex Tank - Fitz's Builds in H40
 Arbites Build - Warhammer 40k: Darktide 

This build's a return to form for Arbi at launch when he was the main frontline tank. He's since been replaced in most comps by Ogryn.

It all functions on a set of connected interactions. The first is 'Arbites Vigilant', which lets you willingly spend your stacks to get 12.5% strength. The second is 'Judicial Force', which lets you stagger everything around you--chaos spawns--every time you reach 0 or 10 stacks again. The separate cooldown is critical for how this build works. Thirdly, the suppression shield's flashbang counts as a stagger hit. And lastly, Lethal Proximity on the Bistol extends the range of 'Judicial Force', because it's an AOE circle around you.

Putting all this together, you have a way to spend 10 stacks, get a 12 second 12.5 strength buff, and knock everything over every 5 seconds with the ability to instantly build 10 stacks again and knock everything over independently, each with a 5 second cooldown and Break The line with a 17 or so s cooldown by itself. 

So, the gameplay loop is simple in principle: charge, knock stuff over, deal damage. After 5 seconds, flashbang, knock everything over, deal damage. By the time your previous buff runs out, you already have 10 stacks to spend again, so next charge you repeat again, until everything in front of you is dead.

Take Arbi nades to save teammates from afar and more DPS or Shmines to maintain Forceful 10 up constantly, though I like this far less. Also, remember that Final Toll will negate your Shmines.

You can also run Nuncio if you like but your uptime won't be as high. Still really funny to knock things over with a propaganda speaker.