Kaiba spoilers for the entire series since this takes place afterwards; this is all my own headcannon because I craved more content. The logistics probably don't work but idc im awesome.
greg soup theyre soup
When the Kaiba plant was destroyed, the remaining biological matter, memories and memory-erasing clouds swirled into an enourmous storm that surrounded the planet Lala (I think that's what the main planet is called?). The surface of the planet was hit with a heavy rainstorm, everything in the clouds falling back down on the planet. Whoever was left on the surface quickly fled to the inner planet to avoid the floods. This created the perfect primordial soup. After a certain period of time the rains slowed, which gave time for new life to spring up. Since it is relitively easy for new bodies to be created in this universe, it is no wonder half-baked memories and DNA mixed with the right ingredients created new life forms.
The storm birthed creatures that looked like mud zombies. Many of them falling apart before being able to fully form. Without a strong enough concentration of memories, or memories that were too fragmented and from too many people, were unable to properly hold together a body. Most of the blobs were vaguely human.
Sate and Popo's memories erased with the horeito happened to drift together into the atmosphere, and combined as a result of the storm. Luckily, or rather, more unfortunately, these memories ended up in the right place at the right time and a body began to form, the DNA jigsawing itself together.
Returning Home
At some point after becoming somewhat collected, Gregory goes in search of the Issoudan base. Upon arrival, it is strangely empty. Quietly snooping around, it seems people were there not too long ago, yet they are definitely not there anymore. Sate at the head, returns them to her room, in search of clothes. They exchange arguments but continue shuffling through her clothes as it is the only thing to loosely fit them. They don one of Sate's jackets, a pair tight white pants, black boots, and a pair of Popo's gloves. A fitting compromise for the both of them.
Reunion with Kichi
idk when exactly, but Greg finds Kichi at some point. He is the tired dad of this AU. Both of them are understandably nervous for different reasons, but they do their best to explain what is happening. Kichi, albeit surprised, isn't in complete disbelief. He knows a lot about memories and their properties, and decides their situation isn't improbable.
Kichi is really stressed out over the recent events, but also do to the fact he has been trying to help baby the people who lost their memories. Namely Sate and Popo's original bodies. At this point, Cheki has made a bit of a recovery with Kichi's help. Even without memories, those pathways still exist in the brain and can be coaxed into remembering what was lost. Without supernatural intervention (like Kaiba's powers), it is a careful and difficult process, but Kichi happens to be the perfect person to handle something like it (my favorite little therapist).
Trying to handle one thing at a time, Kichi says okay lets just put aside everything that has happened and just focus on what's going on right here. Gregory has trouble taking things seriously and becomes increasingly loopy as Popo's will starts taking over, though really the combined consciousness has been in a state of disassociation. Kichi is starting to lose it and he becomes forceful. Like. If you can't take this seriously and if you don't try I'm not going to help you at all. I know you think this is funny and you think it's funny to annoy me but it's not helping. I have to figure out what to do with you as well as your original bodies.
They eventually settle down and try to have a serious talk with Kichi, but not before some unexpected visitors. What are almost empty shells of the real Popo and Sate walk into the doorway, curiously peering at the situation. Gregory is obviously like, freaked out as shit. and is like. what the fuck. so they just kinda sit there like ah ha ha. Sate's body is like Kichi... who ...i s... tha.t.... and he is like uhmmhmhmm dont worry about it go back to your room.
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Eventually, Greg realizes there's something very wrong with their body. It wasn't apparent at first, since Sate is used to living in a body with mechanical issues, and it's not Popo's first time trying to get used to a new body, but their new body seems to be falling apart. It begins to loose a formation of real skin, instead becoming gooey like the strange purple substance they awoke from. After Kichi examines it, he believes it is akin to a cancer, growing and spreading through the body. He fears their body may not last much longer if the "infection" keeps spreading. Kichi feels he cannot ethically try to place their memories back into their original bodies, as they have essentially become new people. He is not even sure if he can seperate their memories at all. He gestures to his memory storage creatures, the likes of Hyo-hyo. It is the last resort, and may be the best thing he can do for them. Gregory is taken aback, not certain if they want to accept this fate. Do they continue to live and be confined to a memory prison? Do they succumb to their true fate?
With a newfound purpose and a ticking clock, they attempt to help reconstruct the world, and right their wrongs, without the force of technology.
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in da end or whatever, Popo and Sate's sense of individuality dissapates and they truly become a new person. The sense of "we" disappears and there is only "I". They question if they were really someone else to begin with (basically gaslighting themselves). How many boards can you replace in a ship until it is no longer the same ship? It shows the journey from uncertainty to certainty (but not exactly). Their story is really about accepting the absurdity of being alive.
