Celestial Power Proc Behavior

I’m curious what triggers certain celestial powers to proc. For instance, on my bleed/vit Trickster I use the Huntress’ Rend tagged onto my devouring swarm and I have noticed strange discrepancies with applications of the debuff. From my observations, it appears to be tied to the damage portion as I see the debuff apply to monsters who catch the swarm through contact with other infected monsters and not just those hit by the “projectile”.

It also seems like sometimes the debuff does not apply at all and requires several Swarms to get the debuff up, leading me to believe it may be tied to the monsters resistances or something similar. Also seems like the debuff will apply to all affected monsters at once, implying the game rolls only once per skill application for whether the debuff will be applied or not.

So to use Rend as an example, it has a 20% chance of applying with Devouring Swarm, I hit a pack of 5 monsters, it will roll the dice and if it is a “hit”, all 5 monsters get the debuff, but if it fails, no one gets the debuff. As opposed to rolling individually for each monster hit, which would make it (in this case) a 100% chance of applying on paper. Can anyone clarify on this?

My other question is, will each tick of devouring swarm roll another chance, or is it rolled only once when I initially use the skill? I have heard of strange cases of debuff applications elsewhere such as the fire resist reduction on OFF being tied to the snare and not the debuff/damage.

For powers attached to attacks, it’s whenever you use that attack and (I believe) every second it’s applied. So if for example you have Eldritch Fire (the solael’s witchblade power) attached to Curse of Frailty, every time you apply CoF and every second of duration thereafter has a 15% chance of setting a given target on fire. This % chance is per enemy hit so you could get insanely lucky and have them all ignite on the first go, or be really unlucky and have none of them ignite, or more likely have a few catch and the rest get it after a second or three.

For powers attached to an aura, it’s a % chance whenever you’re hit by any enemy’s attack.

The point that you’re missing is that Rend has a radius. So you cast Devouring Swarm and tag X monsters with the bees. Rend will roll a 20% chance against each affected monster, each second; when that roll succeeds, all monsters within 2-5 meters (based on Rend level) of the lucky winner get tagged with the Rend effect.

Ah, I did miss the radius in the tooltip, that explains a lot, thanks for the replies