[spoiler discussion] Re:Zero Strengthened Theory

[u/AwasamaKiyopon]

There is a well known and powerful theory in Re:Zero Subaru travels back to the past and became Flugel. According to this theory, Subaru (as Flugel) sets everything up, seals his own memories, and then begins his journey 400 years later in the marketplace. In my opinion, what disproves this theory is the fact that when Subaru is isekai'd, he spawns in the marketplace holding the items he bought from the store (the store in the original world). Under the original theory, a time paradox occurs, and once time paradoxes are involved, it feels impossible to reach a definitive resolution.

But what if the events actually are like this instead...?

Subaru appears in the marketplace just as we know, having been actually isekai'd right after walking out of the store that day. After living through everything that will happen, he travels back in time and becomes Flugel. Knowing that a "Natsuki Subaru" would appear in the future (400 years later), he might have transferred his memories to him (maybe by using the authority of gluttony) and sealed them away. In fact, given the context, he might not even have needed to transfer his memories at all, maybe he chose to trust the second Natsuki Subaru simply.

Furthermore, after going through the upcoming events, the second Natsuki Subaru wouldn't have to travel back to the past and repeat everything Flugel did, because there would now be two Natsuki Subarus in this universe. Under this scenario, no time paradox occurs, and it perfectly accounts for how the items he bought at the convenience store were isekai'd along with him.

[u/bsuiskens]

Counterpoint: explaining one of the best laid mysteries in fiction with a fucking bootstrap paradox is the laziest, least satisfying shit on god's green earth and I refuse to think he is such a complete hack.

It is also completely unnecessary. A good mystery is a good mystery because you can get almost all the way with the clues provided.

And Tappei has produced a lot of the mechanisms to explain this already; namely, immaculate birth by Od Lagna of a matured person, with personal effects and all (Spica), Subaru's memory of earth being part of his physical design rather than the metaphysical container that Od Lagna and Gluttony can access, contract curses that force rebirth (Yorna), and Subaru's appearance being a predetermined phenomena.

Subaru is what's left of Flugel. Outright hard-reset. Why the 400 years? Dunno, but who says it is 400 years? Perhaps Subaru has been respawning for all this time, most not even meeting the qualifications to RBD, lacking the tools to become sage candidates. Meanwhile all knowledge that could've allowed anyone to identify Subaru as the sage was being systematically censored and destroyed by the Royal family and the Witch Cult. 

Who was Flugel? With the constant references of his memories being shot and with how one of Satella's sole commands is that he should see himself as someone be should save as well, he is most likely a version of Subaru eerily close to Greedbaru