would have to go with blessgiver
the nids are not immune to instant death from it, because its not a double strength weapon as it says in the codex, unless im missing something
plus ini 6 owns chaplains and other characters.
the plague sword is just as effective, if not more so than taking out toughness 4 or lower, in 5th edition poison rules, did any1 check them out, how cool. but really hard to kill tough 5 or more guys, with an avg of about 1.44 wounds, where with the bless all u need is one wound, which isnt that hard to do. plus beating a tyrant in combat and outright killing it on first turn charge, is something i wanna see.