Your existence is entirely unique. Not only are there no other versions of 'you' in the omniverse, but any attempt to interact with an alternative version of you is doomed to fail. A time traveler cannot change your past since 'past you' is non-existent and neither can a precognitive predict your future since 'future you' is just as non-existent. This singularity of self has given rise to the ability to 'shift', travelling to parallel versions of the world you inhabit, taking the place of your non-existent alternative. With enough time and effort nearly any version of a world can be shifted to, with the only invariant being the complete absence of yourself. The greater the differences between your current world and the one you are attempting to visit, the more difficult the transition. Visiting an entirely identical world (excepting any changes you've made) would be instantaneous while travelling across setting might require months of charge up and incredible focus. Due to the sheer density of parallel worlds shifting allows access to and your absolute lack of multiversal presence tracking you across shifts is completely impossible.