Quote Originally Posted by Iscah View Post
I don't think the story needs to "establish" that the two timelines are on the same branch. That seems like the basic assumption to me, while the idea of them splitting into fully parallel worlds seems odd and much harder to reconcile with the known story.

G'raha travels back in time along a single timeline (as he knows it) and his actions cause a second timeline to branch off from the first one. It seems far more natural to picture that as a branching structure than a duplication of everything.
The nature of G'raha's time travel, that is to say going through the interdimensional rift, would suggest from the start that we're dealing with parallel timelines and not divergent timelines. After all with both Alexander and Elpis, events are ultimately causal loops - the future remains completely unchanged from the time travel, or more accurately it was always this way, which was not the case with G'raha.