Disaster / Destruction
With the each shrine locked away by The Serpents Alliance magic began to dwindle and soon became nonexistent all of Urmur's influence was cutoff. With hundreds of years of development the Thalma cities grew dependent on magic everything from their food to the infrastructure of their buildings required magic to sustain themselves. So as Nathlia hid away with the vines of Urm her people and all they had created collapsed leaving nothing behind but the few relics of their time.