I've been thinking about a few key things that were mentioned during the ending of Union X which I feel could spark an interesting theory, more specifically regarding the arrival of Lauriam, Elrena and (potentially) Skuld in what we can call the "current era" of the timeline. I've searched discussions about this in the forums and found nothing, but if someone has already talked about this somewhere I'm truly sorry for having missed it.
Anyway... Basically, there are three questions we want answers for, regarding these three individuals:
A) Who the hell remembers who they were;
B) Why they were rebuilt at the locations they were shown to be at Union X/ KH3 Secret Reports;
C) Which medium was used to bring them back to the current era.
Now, I don't have a concrete answer for the third question, and to be honest nothing in particular seems striking to me about them that could be used as a medium. The second one I can offer a partial explanation, at best; as for the first one, however, I have a theory as to how they were rebuilt.
I believe that their return is a consequence of Terranort's experiments on the heart during his time as an apprentice of Ansem the Wise. My evidence for that:
Anyway... Basically, there are three questions we want answers for, regarding these three individuals:
A) Who the hell remembers who they were;
B) Why they were rebuilt at the locations they were shown to be at Union X/ KH3 Secret Reports;
C) Which medium was used to bring them back to the current era.
Now, I don't have a concrete answer for the third question, and to be honest nothing in particular seems striking to me about them that could be used as a medium. The second one I can offer a partial explanation, at best; as for the first one, however, I have a theory as to how they were rebuilt.
I believe that their return is a consequence of Terranort's experiments on the heart during his time as an apprentice of Ansem the Wise. My evidence for that:
- In KH3, while Larxene and Marluxia are reunited at the thirteen "seats" on the Keyblade Graveyard, they soon are joined by Demyx, Luxord, and most importantly, Xemnas, who mentions that all four of them will reveal their "greatest secret": the ancient Keyblade War legacy that slumbers within them. This means that Xemnas, and therefore, Xehanort, has some knowledge of who they are, albeit incomplete knowledge. Why? My reason for that comes in the next point;
- Before Xehanort was conducting his research on the heart, he was actually the subject for Ansem the Wise's research. Why is this important? Well, since the ending of Union X heavily implies (because it's not fully confirmed but it's pretty much assumed to be true) that Xehanort is our player's reincarnation; since the Player has the knowledge of who Skuld, Lauriam and Subject X (if, again, she's Skuld) are, and since Dark Road tells us that Xehanort has fragments of the Player's memories, I can assume that Ansem's experiments led to him being able to tap into those memories and this is how Skuld, as Subject X, was recompleted/rebuilt at Radiant Garden;
- The continued experimentation by Xehanort, shown in KH3's secret reports, must have had the consequence of Skuld's heart having fragments of memories from Lauriam and Elrena; however, since those memories themselves are fragmented, they were partially recompleted - without their own memories, which would explain why they have no memory whatsoever of the events of X/Unchained X/Union X. I can't seem to find a good reason as to why they reappeared where they reappeared, though; I can't trace a connection between Lauriam and Dwarf Woodlands, nor one between Elrena and Enchanted Dominion;
- At least one of Ansem, Seeker of Darkness and Xemnas seems to have continued their research on the heart - most likely Xemnas, again due to the KH3 scene mentioned earlier. This explains why Xemnas has some knowledge about the KHUX era, and points to Terranort's obsession with "who he was before his amnesia" being even more eventful due to his wanting to understand why he has the memories he was shown to have in Dark Road.
- Ansem the Wise must have found something about the UX era while researching Xehanort's heart. How much does he know? Why hasn't he shared anything about it with us yet? As Xehanort puts it in KH3's Secret Report 3: "Ansem the Wise ceased his research into the heart, his hand stayed by some fear I cannot fathom.", so there definitely is something there.
- If Skuld was recompleted at Radiant Garden, how did the medium used to bring her back found its way to Radiant Garden? Was something left on her lifeboat, which upon a new machine being built led to her return? Also, similar questions can be asked about Lauriam and Elrena's mediums.
- We learned at the end of Melody of Memory that Kairi was one Terranort's subjects, sent via lifeboat to Destiny Islands. Since no one there could have remembered who she was (unless some shady shenanigans were going on with the cloaked figure remembering who she was somehow), did Xehanort perfect the lifeboat's design enough to allow a person's physical body to arrive intact at their destination? If so, that's an amazing accomplishment, something that not even the Master of Masters was able to do.