Arbites
10-25% Damage vs Electrocuted enemies.
Target receives 1-4 Stack(s) of 10% Damage if already Staggered. Lasts 5s.
Gain 7-10% Close Damage for 3.5 seconds after killing an enemy at close range, stacking 5 times.
14-20% Strength for 5s when every pellet in a shot hits the same enemy.
Without a red stim and using the shotgun, this build can:
ONE-SHOT reapers,
ONE-SHOT bulwarks, and,
ONE-SHOT crushers.
It can also reliably/easily/always TWO-SHOT all ogryns (e.g. crushers) without any special or complicated setup i.e. in an emergency.
I have also one-shot maulers without a stim but that requires combat to be underway (so that you've built up some stacks of things).
If you do some talent tree re-works (not included in this build, but feel free to figure it out) plus red stim plus using the bolter instead of the shotgun, it can KILL TWO BEASTS OF NURGLE IN TEN SECONDS (during a single use of castigators stance. I *think* I also killed two plague ogryns in ten seconds but I don't recall (if I didn't kill the second, he was one-hit away from death... but I recall maybe I pulled it off). I managed to screenshot 26374 DPS during testing (see pic).
During testing I was able to kill ten crushers within ten seconds with a red stim, castigator's stance, and using a bolter as described.
For this particular build, I dropped the extremes of the possible DPS (who needs to kill two bosses every ten seconds?) of that overkill build and went shotgun plus added some survivability so that it can be used in missions without feeling like a massive glass cannon. Plus, the shotgun has more utility against snipers etc and fights better in CQB compared to the bolter. When waves of elites come to overwhelm you and start dropping your allies, you will be able to go Doom Slayer Rage Mode and absolutely drop everything in seconds.
The melee weapon of this build doesn't matter. I like the shock maul or even the tac axe just for mobility. You won't need to use it if you have ammo :)