Okay, I was wanting to mess with Bladefall and spell cascade for a bit, Put it in a 3 link with my current build, which is the Essence drain Shadow, so I focus on DoT damage primarily, but there are those incidental Chaos/Phys hybrid nodes.
Anyway, I 3 linked it with Cascade and Decay.
Holy balls. I think this is the spell to use for poison. All the individual knives just spam the area in 15 waves. 5 waves x 3 because of cascade.
I think a large hitbox mob will get hit about 20 times per cast, very easily. So 20 poisons, with the right build. Along with the other poison focused stuff. The area it covers is also huge, if you target your feet it starts a few meters behind you and touches the edge of your screen, and about 10 meters wide. Just incredible.