Galerion cried, echoing, "Worm King, surrender your artifacts,
And their power to me, and you shall live as befits the dead."
The hollow laugh of Mannimarco answered: "You die first."
The mage army then clashed with the obscene and unholy force. - Mannimarco, King of Worms
I was reading up on the lore and found this. From what I've read this seems to happen in the second Era. I think this would be a nice idea to incorporate into a new story-line for the game.
As a side note, the lore is a maze to get through regarding finding out what happened when and such. But many interesting ideas there for continuation of the story in ESO.
Source:
http://www.uesp.net/wiki/Lore:Vanus_Galerion#The_Great_Battle
What are your thoughts on this?