back in the old 2e adventure, Die, Vecna, Die!, a connection between the Lady and the Serpent(who is behind Vecna's rise to power) was made.
And here's a thought-
There's a Lady who controls a city that may the source of all Belief in the Multiverse, where a single God could convert reality to whatever it believes. To maintain Free Will, the Lady holds at bay the Gods, preventing a single belief controlling the soul of the plains.
Perhaps there's a Spire beneath the city, the gathering and transmission point for all magic. Controled by a Serpent who prevents any other from tapping into enough magic to undo Creation in the simpilest way possible- by denying all beings other then itself from using any form of magic
when in proximity to said Spire.