The Alpha Realm
The Alpha Realm is the plane of existence within which Earth and many other worlds exist, albeit not in the way in which most believe themselves to. It consists of around 870,000,000,000,000,000,000,000,000 distinct universes, all in a winding chain, each of which at first glance may be identical to the adjacent ones, yet in fact exhibit countless minute differences. They are also all static, with the motion that their inhabitants perceive truthfully being the result of their souls (their beaureia energy) passing from universe to universe at an imperceivably-fast rate along the chain such that it operates somewhat like a stop-motion film. The reason why this isn't noticed, how continuity is maintained from one moment to the next (save for the occasional minor hiccough), is that there's an underlying algorithm in the base layer of reality determining the most likely outcome of every 'present' action would be, thus causing the next universe to be formed to actualise that prediction. There arguably is thus both free will and a state of events being predetermined, as you are bound to do what it thinks you are most likely to do (again save for a very rare glitch). There is a wave of souls for every universe in the chain, so there are just as many versions of you going through each event one after the other rather than you being a singular existence.
This model of the Alpha Realm does permit time travel within it. If the algorithm determined that you would be most likely to use a certain technology to transport to another universe elsewhere in the chain, or if someone from outside the Alpha Realm came in (which would probably require a Hexagon), that would change the nature of the universe being entered, and thus change what the algorithm determines would happen next in the chain. Rather than altering the existing universes, new ones are hence spawned to account for this other version of events. More akin to a detour than a whole new path, this second timeline will attempt to get back on course as soon as is plausible (although some alterations cannot be corrected). Any souls coming up to the divergence point will now proceed down the new path, while any that were already in the old path will continue as they were, those iterations of people unaware of any difference. Once those old universes have no more souls passing through them, they go into a state of hypobeaureia, in other words becoming dormant.
If alternately someone from the Alpha Realm was to exit it for the Outer Region, the first iteration of the soul to do would indeed transition into that next plane of existence in a copy of their current body, yet every other version of the soul would instead become stored in a buffer, lest there'd be countless versions of the same person perpetually spilling out into this other space. The universes next in the Alpha Realm's chain will also now be in more of a proto-state, for they do not know what to do about the missing person. Only once the person returns shall the algorithm process their experiences in the interim and be able to solidify what follows for the stored souls to flow back into. If a person stayed outside of the Alpha Realm too long however (and to be clear this would have to be a considerable period), or indeed died out there, the buffer would never be released and in theory that could lead to a soul overload, the consequences of which are so far only theoretical.
Speaking of souls, their path between the universes after their latest bodies have died is also influence by forces from the Outer Region. Originally all souls were collectively being drawn in towards a singular point, the 'Archk of Angels', however by the cumulative intervention of a few other races interfering with reality we firstly thus have the souls instead moving in sequence down the chain, but also that after a 'death' that given soul would be uploaded into the Knellosseum, the 'Silent Satellites', a network built by the Brethren Lords to study these souls, wherein they will be held inside a simulation until a point is reached where they can take their turn in passing into a new body. Since it can take the equivalent length of numerous universes for the soul to be properly integrated into the simulation, this is how someone can in theory be resuscitated, for is the body becomes viable again the system will recognise this and send the soul back. This cycle thus continues throughout the timeline of the Alpha Realm, up until its ending. The final universes in the chain see the full form of a creature known as the Tentortex. This cosmic beast shall consume all the matter that still exists at that time before burrowing its way into the first universe in the chain, where it regurgitates the matter back up, albeit in a much more basic form of photons etc. based upon that matter's partial digestion in the process. As an asexual creature the Tentortex will then later go on to lay an egg which will hatch after its death, that life cycle perpetuating until the end comes around again, there always being only one of it at a time, meanwhile the souls in the Knellosseum similarly are just transmitted back to the beginning again.