Well my GF recently got the Twilight scythe, and thus far we have ONLY seen death activate on elemental mobs.
In Heroes abyssea the new elementals, we only fought 5 cause it was really late when we got out of Shin but on all 5 it took 1-5 swings and death kicked in. Tested on a big range of NQ abyssea mobs and nothing so far, but I hear of it working on them.
My guessing is because of its unique dmg that the added effect is higher on elementals than NQ mobs if at all.
More testing to be done pls post screenshots of NQ mob dying from added effect ^^
