I separated the Ghostly Infusion from Bolt to prevent too much visual noise from occurring on this set because I have recently grown to resent the absurd noise from a lot of peoples outfits.
With that out of the way the Shoulder's are a skin that can be acquired from a PoF collection achievement that would take roughly an afternoon's worth of participating in events.
I'm not one for writing lore but I do like making outfits, will work on a Norn Medium armor style next.