Soul Feast currently says that it works on targets who are “marked for death” alluding to the Marked for Death Curse skill (and probably Soul Bastion shield). However, Soul Feast also currently targets Spirit Plague Cursed targets. So one of two things are happening:
-
Soul Feast is meant to only work with MfD, but was created to target cursed targets specifically. Marked for Death was the only curse (as far as I can tell) until Spirit Plague was made, and this is an oversight.
-
Soul Feast is meant to target any cursed target, and the tooltip just needs to be updated to reflect that it targets cursed enemies (and that Spirit Plague is marked as a curse).
Personally I think 2 is more likely (and the better design choice for variety’s sake).