No matter how powerful they are, all Umbra witches are destined for Inferno in the end - a place full of perverse demonic abominations, hungry for fresh toys.
There your soul gets violated and consumed like fucking meat, except you can't really perish in Inferno. Your soul is used to breed disgusting demonic spawns while slowly getting drained and digested inside the fleshy abominations, but just when you think you finally cease to exist, you fully regenerate to go over the breeding and digestion once again.
The line between pain and pleasure eventually fades away. Whichever it is, one thing is for certain: it is never ending.