
Here’s my theory: Guwon was some high-level military officer in the past—he’s huge, towering over everyone, with long, strong limbs and the physique of someone well-trained. I believe the collapse was predicted—or at least expected—by the national government and scientists, and only those in the upper echelons of government and society were alerted to the impending disaster.
Stick with me now. Who would be able to afford bunkers or safe houses in the event of a catastrophe? Those with money and power. And ironically, the very safe haven Guwon protects is just that.
Back to Guwon. In some shape or form, he “died”—not completely, but the person known as Guwon was effectively erased. That would explain why he now has the understanding of, if not less than, a first grader. The Guwon we see today, I believe, is the result of a failed Frankenstein-like experiment. They wanted a mindless zombie that obeyed only one command: protect the safe haven. He had the perfect build to endure such experimentation and was, in some ways, a success—demonstrating superhuman strength, stamina, and instincts.
And just like they intended, he doesn’t know how to read, he doesn’t understand social cues, and he’s completely oblivious to how society functions. Guwon was revived solely to protect this elite community of the ultra-powerful and wealthy. That’s why values like order, law, justice, fairness, and duty take utmost priority for him—he was literally created to uphold them within the walls of this sanctuary and shield those inside from the chaos outside.
All of this happened before the collapse. But obviously, something went wrong. Where are the people he was supposed to protect? In my opinion, either:
A) He killed them himself, or
B) The apocalypse took them out before they ever made it to safety.
Either way, they’re gone, leaving Guwon—this loyal dog—protecting something that no longer exists, waiting for his masters to return.
Instead of continuing to wait, Guwon began retrieving people to protect on his own, building a society within the limits of his understanding. He goes through the motions, again and again, collecting people to fill roles… Sound familiar?
Just like Sisyphus, endlessly pushing the boulder up the mountain, Guwon repeats his task—maintaining this “safe haven” even if it causes more harm than good.
Mic drop.

I’m leaning towards artificially created super soldier/super mutant. Like some shit from the Fallout videogames or something. It would explain why he doesn’t remember anything about his past. He may not actually have a past to remember if he was just built in a lab by scientists. Deliberately created to seek out and find the most “worthy” survivors for some purpose. Might be some eugenics effort or something.

Definitely interesting theory, it is mentioned by the vet near the beginning that some of the original wealthy inhabitants are still living there because they "need" them tho it's not explained what that means, though when we first see guwon it seems like he is just discovering(?) the town though it could have just been his first time actually inside one of the houses with him bring like I've always wanted to live in one of these places or smth like that iirc
Aside him being a confirmed nutjob with no way to gauge his morality, that bathroom scene sent a tingle down my spine ( ̄ε(# ̄)Σ