Wraith of Agony

At the beginning of your upkeep give -0/-1
to each Prisoner target Judged opponent controls.
When Wraith of Agony dies target Judged opponent
gains 4 life for each Prisoner they control.
Only when a wraith of agony dies will the prisoners
feel any relief. Take care to find and kill it quickly,
lest their torment overcome them.
We shall judge the mark of your success.'
— Words of The Tribunal.