Originally Posted by
astrael
I'm surprised that this idea hasn't been brought up about Nyzul Weapons yet: I think the addition of storing it with the Salvage NPC is a good indication that the hidden effect is not available unless you have a completed Salvage armor set worn with it. And since no one has been able to complete a full set, it would explain why no one has been able to figure out what these weapons actually do.
S-E said two updates ago that they were sure that people would start seeing their value, probably assuming we'd have solved the mystery of Zhayolm Remnants NMs by now. It just makes too much sense if they are storing the weapons with the Salvage armor in progress that they go with.
As for the hidden effects themselves, I have two guesses - either they are going to be based on their name and thus different for each weapon (eg. Quicksilver would have Rapid Shot enhancement or Dancing Dagger adds Triple Attack), or they are going to enhance the "Set" bonus of the Salvage armor (increased Double Attack rate or whatever the case may be). We probably won't see any increase in DMG or improved Delay for the most part though.