12-24% Rending on Enemy Weak Spot Hit for 3.5s. Stacks 5 times.
5-8 Bleed Stacks on Critical Hit.
4.5-6% Close Range damage on Repeated Hit. Stacks 5 times.
Gain 7-10% Close Damage for 3.5 seconds after killing an enemy at close range, stacking 5 times.
Go for the heads. Your focus is shooting specialists and elites. Don't be an ammo magnet, only shoot high priority targets, not trash mobs.
You can use any melee weapon you feel confident with that provides defenses in the form of mobility or good crowd control. Rapier or regular Shovel would be my picks if I were to replace knife.