The world was unformed, shrouded by fog. A land of grey crags, arch-trees and everlasting dragons. Then there was Fire, and with Fire came Disparity.
Or that how the story goes.
Then Gywn linked the Flame to Humanity, the undead curse came into being and when the Flame fades it draws the embers from Humanity. Thus Flame must be fed new kindling.
Fortold to happen that the First Flame dies.
Where the transitory lands of the Lords of Cinder converge
, is to tell us that the lands that visited are not from the same time era/line, but are connected to the lords.
From the base game, we saw that Sulyvahn was one of the beings that was exploring the converged land, first finding the Profaned Flame, recruiting the survivors, taking over Irithyll Dungeon, imprisoning Gwyndolin, currying favours with Aldritch and sending knights to stop the linking the flame. This showed that Sulyvahn was active and likely to have lived outside of this cycle, which we found out to be true in the DLC.
Sadly Gwynevere isn’t anybody in DS3, and she is unlikely to have existing as anything other than an illusion to protect the image of the gods1 and pass on the Legend of the Chosen Undead.
Gwyndolin, all too aware of his repulsive, frail appearance, created the illusion of a sister Gwynevere
Just like Gwynevere, she is a illusion inspired by Priscilla to continue on the legacy of the Darkmoon, while Gwyndolin was slowly being devoured.