Graizur wrote:"The Stranger" is a relationship between the U in URU and the multi-dimensional universe of the D'ni.
Kind of like your theorecptical ability to travel back in time and change the present, but only the parts that you don't know about, because the rules of reality account for conciousness.
I'm paraphrasing (superphrasing?) what I've read in several interviews I've read and interviews so many of us have watched where Cyan, specifically Rand or Robyn Miller talk about the player is you. In my shard it is I who rescued Atrus from his prison and then ventured into Riven with on a mission , and some books Atrus had given.
This depends on which of the Millers you hold as the "authority" on the D'ni and Myst universe. This very long MOULa thread provides some enlightening points about the differences between Robyn and Rand/RAWA's perspectives on this.