Her skill is "Miracles" and it can remove single enemy (more like an instant death but deal no damage). Nubee have something like "instant death skills" before. But when I used it, it just a normal attack with more damage than before - absolutely not an death immediately. And then "instant death skill" have been removed and change by "critical hit".
This card seems like a lot to Hecate :)
Since it's is like an instant death, I decided it can't be too regular. So I make it 1% chance :)
If you use her skill when subdue Archwitch then the AW will be removed. No chest for you :(
And here is her status:
Though the chance to get her use the skill is pretty low but it is not impossible: