Includes spoilers until 3.2. Amphoreus is a giant experiment of Nous and Fuli made from Cyrene's memories (like the simulated universe) to study the universe and the aeons and Phainon and the flame reaver are memory fragments of Nanook

The title sums up everything actually. Nous and Fuli wanted to study the universe and aeons. They do this by capturing Cyrene, who happens to have witnessed Nanook's ascension to aeonhood. This also explains why she's an emanator of remembrance. Fuli extracted her memories to simulate Amphoreus and Nous used Lygus to keep her trapped. Which means, they were the only real beings there until DH and TB arrived. Phainon is the fragment of Nanook before the tragedy that changed him happened and the Flame Reaver is that of Nanook after it had passed, so he's not an aeon yet. Similarly, Mem and March 7th are also fragments of Cyrene. This should explain why in Luofu she was told that accessing her memories would be dangerous. Her memories probably hold the key to discovering the very existence of the universe and its other secrets since she saw the ascension of an aeon and consequently, knows how it works.

Coming back to FV, he has realised that this is a prison and wants to set Cyrene free. The problem is, he isn't strong enough to defy two aeons. However, he might have a chance if he manages to retrieve all the core flames. This isn't because the core flames would strengthen him, nope. I think that the core flames are sort of like the restart/revive buttons. The black tide ends the current cycle once the core flames are in place. Therefore, if you don't let that happen, the cycle will not end and instead, there's a very real chance that the whole thing will crash and free Cyrene. Fortunately, he isn't the only one on this mission. Cyrene is also doing what she can to free herself and this is where Mem comes in.

When the train crashed into Amphoreus, DH and TB run into Mem immediately who takes them to Phainon. The nameless are a brand new variable here who could be the final missing puzzle to destroy this elaborate prison. And that's exactly how Cyrene intends to use them. She initially guides them to the main cast as Mem and dissappears. Then, Oronyx gives her to TB because she's also in on Cyrene's plan.

The next step in this plan is to join the two fragments aka Phainon and FV, like how the strife titan was revived(?). That would complete the dream team and now, TB, DH and Phainon along with mem rush to destroy Nous' simulated universe.

This part is my explanation for the scene from the trailer where mem rushes to TB who then destroys everything around herself with her new feather weapon(?). This is immediately followed by Cyrene emerging and hugging her from behind. I think that's what's happened there. The TB along with Mem destroy the prison and free Cyrene. Meanwhile, DH and Phainon are probably dealing with the coreflames.

The rest of the astral express joined them on Amphoreus after Herta realised what was going on there. So I'm assuming they'll split into three teams: one to safe-guard March 7th, another to deal with the coreflames and Lygus (who's there to ensure that Cyrene stays trapped) and the last one to go destroy the prison with Mem and TB.

When it all ends, these fragments of Nanook also dissappear and all that's left is a complete Cyrene. March 7th was her physical body that was probably sent to find help from outside. With its purpose fulfilled, it is no longer an empty shell. She is now complete with all her memories.

The "deaths" and other story inconsistencies can also be explained in this theory by assuming that since everyone is a minor memory fragment, they're used like code to rewrite into the next setting, aka "reincarnation". When TB "died", they rebooted the system by installing Castorice and retrieved their lost code which was later rewritten into their existing body. Fuli's gaze was sustaining the body in the absence of this code. The other story inconsistences like Mydei remembering different things about his childhood and life are probably a consequence of this system. He defies death every time. Meaning, his code isn't rewritten into a new "being", instead it found a loophole in the system and rewrites itself back into the existing body. However, since these codes are a form of memory, it is never a neat process and results in such inconsistencies.

That's about it. In the end they pack it up with a healed-to-completion Cyrene/March 7th and the astral express heads to their next destination.

TL;DR is that Amphoreus is Nous and Fuli's version of simulated universe to study the real universe and the aeons. It is made from Cyrene's memories who is the completed form and March 7th and Mem. Phainon and FV are fragments of Nanook created using the memories of Cyrene when she witnessed Nanook's ascension. The astral express destroys amphoreus aka the prison and sets Cyrene free.

This is my first time posting here so if I'm not doing something right, please let me know.

Also, you can always come chat with me on tumblr or twitter. I'm @gunsandmatcha Thanks for reading! Let me know what you guys think about this!