This trophy requires you to earn the Blackest Sacrament achievement, which requires you to kill each of the names on the list. This is a daily quest so you have to check back every single day for a new name or two.
Edited by GoodFella146 on July 17, 2016 7:30AM
I'm at the point now where I've been doing this literally every single day since I've unlocked it (I think 1 or 2 days after DB came out), yes I am still not able to complete it because three names will never ever appear in a daily. I haven't seen a new name in at least two weeks, and it's starting to really get old.
I have never seen Steidor, Daynil Uveleth, nor Eslendore in the past month plus that I've been doing these sacrament quests, and I've been checking literally every singe day without fail.
Something is wrong because the same names keep showing up, never a new name.