Wear both weapons that use Frenzy and Nightfall, then take them off (using other weapons). Inside your combat logsyou will see both Frenzy and Nightfall procs showing up (doing shock x and decay x against your enemy)TL;DR version - As long as you get frenzy and nightfall, you can get the weapon procs from any weapon you swap out (before you die). This means you can find weapon's with better stats and use those for the procs instead.For Witch Elves - it also means that you can go ahead and grab SPITE for an extra free proc and rotate (on a macro) all 3 daggers.

This means that the procs from these weapons are likely from a hidden self buff. That is why they disappear when we die. It's also why we can unequip them and get the procs from any weapon.Bear in mind you still need those daggers in the first place to do the procs (note Brutality doesn't have a DD proc.)