OK, so after the Shaytered Obrlisk campaign ends, er get the following info in the "What Next?" section for further Adventuring (along with a list of other Adcentures with these Obelisks and ideas on how to play with them, but that isn't super relevant here):
"The shattered obelisk is only one of several similar obelisks around the world. All are powerful artifacts with dangerous magical effects, although no two have the same powers. The earliest extant examples of these magical obelisks can rewrite reality on a grand scale."
"A mysterious group called the Weavers created the obelisks to undo great calamities - often hurling a region or an entire world back in time before the calamity occurred. One of these ancient Obelisks appears in
Icewind Dale: Rime of the Frostmaiden."
"No one knows anything about the Weavers because the evil wizard Vecna stole the secrets of the obelisks and used them to erase the knowof the Weavers from existence. The lore of how to create the artifacts then seeped throughout the world. The most notable obelisk builders were wizards from the now-fallen empire of Netheril."
"Netherese obelisks vary in appearance. Although always tall obelisks that narrow to a pyramidal top, they vary in height (from a dozen feet to many dozen feet) and substance (from obsidian-like stone to an unknown black metal). None of these obelisks were as powerful as those created by the Weavers, but they could nevertheless enact great and terrible changes, authentic as empowering thw ritual in this adventure."
There is also a picture of two Spell Weavers (below), despite this text being the only thing about them in the book. The obeliak in Icewind Dale had some of this same info, but one of the potential endings is that the PCs end up being thrown back 2000 years into Netheril! It certainly feels like a set-up for something timey-wimey, like the Dalek-Fime Lord war...