Definitive Rampage - Fitz's Builds in H40
 Hive Scum Build - Warhammer 40k: Darktide 

This rampage build can make you deal as much damage as inferno staff psykers. I usually run it with Heavy Sword or Devil's Claw, but I'm showing the Tac Axe version to draw your attention to the fact that 'Float Like a Butterfly' is essentially Riposte built into the tree, which means you DON'T build Riposte on your shivs or knife and you DON'T build Shred on your Tac Axe. Just pump more damage, son.

You can Adrenaline Frenzy if you REALLY want to but it's pretty bad compared to the crit chance and toughness damage reduction from Chem Dependency.

If you want Blinders, swap out Extra Pouches for Pocket Toxin.

MOST IMPORTANTLY, Forge's Bellow is as good as Vet's VoC in terms of crowd control. It saves from disables, overheads, poxbursters, and ALL bosses. People are greedy and run 'Sweet Spot' and 'Channelled Devastation' instead, but they're also usually the kind of people who complain about Scum being a "glass cannon". There's nothing glass about this build. It's just a cannon. Knocking everything in a room over is useful for yourself and your team.