Originally Posted by
Aucald
It was my understanding that the Pillars of Creation were originally used by the Highborne of Suramar to seal the portal the Legion had created in the Temple of Elune (what would go on to become the Tomb of Sargeras) - this does not necessarily imply that they all returned to their keeping in Suramar. We know that the Eye of Aman'thul did, as it was later used to create the Nightwell, but the Tidestone appeared to be moved to Nar'thalas Academy for study and the Tears of Elune brought to the new Temple of Elune in Val'sharah. It's possible that after the Pillars were used during the War of the Ancients that agents of Neltharion and Odyn recalled their respective Pillars back there and then, and the Highborne's possession of them was only temporarily - meaning that the shield over Suramar was erected solely to defend the Eye of Aman'thul from the Legion (which is probably reason enough given its nature and set of powers). It's also possible that after sealing the portal the Pillars were spread around to use as weapons or defenses against the remaining Legion forces. and were then lost in the upheavals following the Sundering.