fuyuki / Throne

"Time" and "parallel worlds" are concepts that don't exist in the throne or akasha.
Magic and certain psychic abilities have a direct path to akasha. Or better yet, they have a "purer" path than thaumaturgy.
Just like akasha, the throne is at the beginning and the end, as far as us normal folk are concerned.
As far as image goes, it's best to think of all destinations of all parallel worlds converging back to the very first point.
Even a grade schooler could make a better chart than this.
Probably what determines where there is a split into a parallel world aren't individual actions, but an already predetermined "course" planned by the world/nature. On the other hand, this is constantly being led astray from its proper course.
If the exact same person existed in one world, then that world will eventually split in two. Also, those two people will regard each other as natural enemies and will try to remove the other.
On the other hand, it doesn't seem like it is possible to summon a hero who comes from a totally different timeline unless it already comes from a definite past or a relatively close parallel universe. わかんなくなってきた.