Erased: The Town Without Me is a 2016 anime by A-1 Pictures about a 29 year old aspiring manga artist who has a special gift, the ability to rewind time by a small amount, usually a few seconds to five minutes to prevent an accident from happening that usually results in someone's death. Though he's usually successful, it comes at the cost of harming him instead of anyone else. However, his mother is killed by the man responsible for 3 deaths that occurred when he was in 5th grade and, upon her death, he's sent back in time to prevent those deaths to save his mother.
Or at least, that's the theory that's given to us within the first episode. However, for the majority of the series, we're not really given a whole lot of information to go off of. We know that he doesn't go back to the present until all 3 of the original victims died, at which point he saw that he failed but still had an impact, he delayed the death of one of the victims and, though he goes back to the present when he fails, the changes he caused back then still ripple through to the time he resides in.
So, the majority of this theory is going to center on one overarching question: what is his power? Or, to be more accurate, what do we know about this occurrence? Well, we know a few things about it.
Firstly, we know that the power works sort of like a video game section where the game doesn't care whether you win or lose. If you win, the game goes forward with that assumption, if you fail, however, you get a different cutscene indicating the different outcome. If you look at the game Soul Nomad & The World Eaters, you can see this trope in action.
We also know that this power has fail-states. Though Satoru notes that the revivals we see, oh by the way revival is what he calls the occurrence, are not the first ones he's ever experienced, he never directly says that he's forced to repeat the section until he gets it right. Although we do kind of get that, we see that his second attempt was a bit forced, he was only able to do it because he demanded that he get one more try. So, it's safe to say that this power does have fail states and, even though Satoru is usually successful, he can fail and his failure will be shown through his ability to continue from where he left off.
Thirdly, we know this ability is not actually his. While he does call it his, there are several indicators within the show that tell us that this ability belongs to an outside source. Firstly, revival only occurs when a small, glowing butterfly flies by. Prior to the last episode of the anime, I would've thought that that was just a stylistic choice, however, at the very end of the show, this same butterfly flies past his vision and he follows it, he even has a surprised reaction, suggesting that that butterfly actually exists within the world of the show. We also know that it's from an outside source because Satoru himself does not actually decide when or how far to go back. Usually, the revival occurs right as an accident is occurring that he knows nothing about and it takes him back just far enough to realize what is happening and prevent it.
We also know that Satoru isn't given much of an indication of whether he succeeded or failed. We see this as early as episode 1, where a kid was about to be kidnapped by the villain and he goes back by about a minute. He tells his mom to start looking around for an accident or crime and, we know it was successful because the kidnapping didn't occur, however, from the way Satoru was reacting, he doesn't really know what was going on or what he had to prevent. He knew there was something he had to prevent and he did it without knowing what he prevented or what he caused.
This leads me into my next point: if this power were Satoru's and he realized or were given an indication that preventing that kidnapping resulted in his mother's death, which it did, he wouldn't have gone back as far as 1988 to prevent 3 other deaths, he would've just let the initial kid get kidnapped. While it would kill him inside knowing a kid had to die in order to keep his mother alive, considering the revival only had a maximum of 5 minutes on it before, he probably didn't realize that it had the ability to go so far back and thus it wouldn't have occurred to him that he could or should anyway. Or, going in line with this, he would've gone as far back as he could, the initial five minutes, and would've tried to brute force his way to keeping her alive.
Either way, Satoru had no reason to believe that preventing the deaths of Kayo Hinazuki, Aya Nakanishi, and Hiromi Sugita would save his mother because, prior to the revival, he didn't know they had a connection. He realized it when he went back a month before Kayo's death and made the connection on his own that way but, if it weren't forced on him, he would not have any sensible reason to go back to that specific date.
Now, of course, a counter argument could be that of course it's his power because, if it wasn't, he wouldn't have been able to force his final revival and, to be honest, I'm not convinced that's the case. While he did force that one, since all the evidence we have for it is that he screamed really loud, it could either be that it was his doing or the doing of whatever possessed that power initially. We also know that the revival didn't take him to the same starting point: it took him to last possible moment where he had the ability to do something about it. Namely, his date with Kayo at the Science Center.
Even if he knew at that point that that was the last possible checkpoint, the fact that every other revival occurred without his knowledge or consent, suggests that it was because of an outside source.
With this in mind, let's take a look at what we know:
We know that Revival has a sort of checkpoint system, where he goes back in time to prevent something he failed to prevent.
We know that he is allowed to fail.
We know that his actions throughout time ripple into the future regardless of success or failure
We know the power is from an outside source
And we know that Satoru himself is given his mission without clarity
And that's it, really. Nothing beyond that. Or is there? Well, I did some digging, I searched far and wide within the bing search engine and I found the mythos of butterflies within Japan. Butterflies, in Japan, represent a spirit. While it can differ from person to person, generally speaking, butterflies are the spirits of the deceased.
So what's happening? Well, revival only occurs when those butterflies appear onscreen. However, you'll notice that the first two times they happened, there was no death to speak of. While the first one, you could argue was the spirit of the kid who just got hit by the car, the second event had no death and therefore no spirit.
As far as the third revival, the one that takes him back to 1988, it's worth noting that this jump was much further back than Satoru had ever expected it to go, a full 18 years. So, is it the spirit of Kayo? I doubt it.
For one, if it was Kayo's spirit, she would've given him the ability to prevent her death just a little while before it happened so he could do something about it while it's still relevant. There's also the fact that spirits represented by butterflies have some form of emotion attached to them. Though the emotions can be positive or negative, the only way for a spirit butterfly to manifest is if it's connected to who it appears to, and Satoru didn't have a connection to Kayo prior to the beginning of the series. In fact, as Kenya describes, Satoru never really had any connections with anyone prior to the beginning of the series, so the deaths of anyone would be a stretch to say the least.
However, the one revival that the series gets the most focus on takes place right after and to prevent the death of Satoru's mother, Sachiko Fujinuma. So, am I saying that that butterfly is Satoru's mother? Well, yes, let's look at the evidence.
Firstly, revival always takes place after the appearance of a supernatural butterfly and, given how good the direction and symbolism are in this series in general, I don't think it's a coincidence that a show revolving around death and it's prevention would use a symbol that represents spirits.
Also worth considering is that Satoru's biggest revival takes place after his mother's death. Now, normally, I would think that this would just be a coincidence but, the thing is that Sachiko was gathering evidence on the killer who she seemed to know the identity of. If her goal as a spirit was not to have Satoru prevent her death but to fulfill her final mission, the huge jump back to 1988 starts to make a lot more sense.
Also worth considering is the events that happen after the first big revival. Satoru is brought back to the present and is allowed to gather some information and evidence on the crime from Sachiko and her old reporter partner. She may have done this intentionally to prepare Satoru to get it right on a second attempt but there's another tier to this theory that we're not considering: Kayo Hinazuki.
Now, Kayo doesn't have a connection to Satoru prior to the beginning of the series, however, after his first big revival by who I suspect was his mother, he developed a connection with her. Now, Satoru's ability to affect the timeline mean that it's a closed loop and not working on multiverse theory, which means any changes he makes earlier in the chain will affect the chain later down without a problem.
This means that Satoru does not actually have a strong enough connection to Kayo for her to want to prevent her own death until Satoru fails the first time. So, what this could mean is that Sachiko takes Satoru back to attempt to save Kayo, Aya, and Hiromi, and then Kayo is the one who sends him back the second time with a newly renewed lease on people.
Now, what about the final butterfly? The one at the very end of the series? If this theory is to hold true, and butterflies of this type are, in fact, spirits, then whose spirit is that? It may sound irrelevant but, if this theory is to be consistent, we have to account for the final one after his revivals are all used up. And, I didn't want to do this but, this is where it kind of gets dark.
Prior to the 16 minute mark on Episode 12, Satoru completes his mission and gets the killer captured. The killer by the name of Gaku Yashiro. After the 16 minute mark, however, we have a 3 year time skip.
Now, I'm not going to say I know a lot about Japanese law and prison sentences but, what I do know is that, when you're arrested in Japan, you become a criminal and, if you're a criminal, you are treated incredibly poorly, even by prison standards. While I don't necessarily believe that he was executed, the possibility is there that, for the attempted murder, he likely died prior to that 3 year time-skip at the end of the episode.
This butterfly, unlike the others though, doesn't activate a revival for Satoru, instead it directs his attention over to the new arrival, Airi.
For those who haven't seen the series, first, why are you reading a theory that probably has spoilers everywhere? Go watch the series first, dumbass! Secondly, Airi is a character who is working at the same pizza place that Satoru is at the beginning of the series during his time in 2006. She helps him a little bit but, what's worth noting is that, Satoru is not the only one who has a connection with her: Gaku Yashiro, the main antagonist, was a city councilman who had meetings with her boss quite frequently and, though he wouldn't know it in the final timeline prior to his death, he knew in the original run that Satoru and Airi were connected and positive with each other.
The final butterfly, is clearly a spirit but it's not trying to erase a prior death, it's just directing him to Airi, someone Satoru lost the connection with in the timeline reset and Yashiro was trying to give it back to him.
Of course, him knowing about Satoru and Airi is pretty tenuous but what helps is that this butterfly doesn't want to rewind time or anything, it's just trying to get Satoru's attention. And, prior to his death, Yashiro states that he can't live without Satoru because Satoru filled the void in his life. I think Yashiro was paying Satoru back for giving him a death that he is content with.
But, why Satoru? We can argue his mother, Kayo, and Yashiro all day long but Satoru is not the only character who could've filled the role, Kenya, Kazu, Yuki, even Osamu and Hiromi would've made decent replacements as main characters, as stupid as that sounds.
Well, you notice how there's a lot of talk about superheroes in the show? It doesn't start showing up verbally until Satoru gets arrested in 2006 but, even earlier we can see imagery of a sentai hero in the form of a toy mask in Satoru's room. Kenya frequently calls him a superhero, at least in the latter half, and Satoru seems to be very fond of the idea of being a hero.
Well, I noticed throughout the series that characters need a hero but frequently are without one. Kayo needed a hero to save her from her mom, Jun Shiratori needed someone to protect him as well, his mom, who is fucking awesome by the way, wants Satoru to be what he aspires to be and may be giving him a chance to, and there are characters like Kenya who want to save the day but can't.
Satoru, on the other hand, can. However, it's not because he's particularly special or gifted. It's because he's an action taker. Remember Kenya? Well, Kenya said that he wanted to be a hero just as much as Satoru and, unlike Satoru, Kenya noticed the bad things happening and was unable to do anything about it because he couldn't bring himself to speak.
Kenya is an intelligent kid, which means he probably didn't speak out of fear of making things worse, which makes him less suitable to be a hero by his own rights but it does make him perfect as a sidekick who serves as a voice of reason. We even see this during Satoru's second big revival, where Satoru is planning on injuring Kayo's mother and Kenya stops him because it's going too far and not the right solution.
Satoru acts, for better or for worse, he makes a decision and then he takes steps toward making that decision a reality. Satoru was chosen because he's the only one who would do anything to save them if he could. Kenya does act, eventually but he needs Satoru to inspire him first.
This is why Satoru was chosen: he was the hero everybody needed, not the one they deserved. We even see that Satoru's actions inspire Kenya to become a lawyer to help solve crimes related to murder and child kidnapping. And, in return, Satoru himself was saved.
So, it is my belief that Satoru was chosen to be the one to save everybody from their respective demons because he's the only one who would if given a choice. Satoru is a hero and he eventually saved the princess.
But, hey, that's just a theory, an After-Thoughts Theory! We'll see if I end up doing more of these.