All we really know is that the First Curse was manufactured before the Last Word, or at least that is implied. Source: Grimiore Card, The First Curse We also know that the original Curse was "Lost to Fire". The exact meaning as to what that means is fair game. It could mean literal fire, or Solar Light or Energy, as the later is most often associated with fire. The First Curse we as guardians own is a replica of the Original. It is also implied that the Original had some sort of powerful effect when killing, referenced by the "Imprecation" Quest Line, as well as Banshee-44 shows clear fear or nervousness when giving us the completed weapon. Also, it is as OP as hell. Edit: In PvE.