Maybe these already have been established or suggested, but whatever.


Theory 1:

I have seen some debate over whether the CoC and the DC and the other guild-quest completers are the same person or not. Ultimately, due to the nature of the Aurbis, famous people aren't remembered in detail very well. It doesn't matter who did what, but that it happened. My theory is that, like the Talos Oversoul, the "hero" of each game is just a condensed representation of the various possibilities happening around the same time. The Nerevarine was somebody who managed to fulfill the role, but it may be that a different person defeated Almalexia, and another fulfilled the Bloodmoon prophecy, etc. It could be that the Agent of Daggerfall was multiple people, producing multiple results creating the Dragon Break.


Theory 2:

This goes along with Theory 1, but the idea is that the games are Elder Scrolls themselves. Elder Scrolls seem to carry different functions, but follow a theme of recording the past. I believe that, like how a game is a condensed representation of the events of that time, the game is an Elder Scroll. You are peering into the events of one or more heroes of the time.

You lost me at Talos Oversoul.