Lord_Inquisitor_Doge wrote:...since the Necrons don't currently have any weapons (that I know of) capable of shattering C'tan, otherwise we probably would have seen some stories about said superweapons.
It is nearly impossible to tell what super weapons the Necrons do or don't have.
GW doesn't like to write stories about them except as generic antagonists, and most of the signs point to Necrons avoiding the use of super weapons. I.E. they have the Celestial Orrery, but they never use it, and according to the fall of Orpheus they have black hole cannons on their ships but they don't destroy planets with them. They also have the ability to destabilize stars and roast their planets, but they rarely do it. There are also thing like the World Engine, which the Necrons either only had one of (and that seems doubtful to me but
YMMV) or they are choosing not to use the others.
Maybe, with a few exceptions, they see deploying super weapons against the younger races like taking out a termite infestation with nuclear weapons.
Back to the topic,
AFAIK while the Blackstone Fortresses may have been made to kill C'tan, and are therefore immensely powerful which is why all the younger races want them, in both the new and old Necron fluff they were never actually successfully deployed against the C'tan. Losing one of the four C'tan in the old fluff would definitely had been noted and in the new fluff the Necrons shared them.