Saito Sejima is the main antagonist of AI: The Somnium Files. His main deal is that he suffers from a brain dysfunction that renders him unable to produce oxytocin, the hormone that allows you to feel affection for others. He does, however, gets a fuckton of serotonin + dopamine from killing things. He eventually grew into a serial killer in his search for pleasure.
A lot of people don’t like Saito. I can certainly see why. I’m sure your reaction reading this paragraph was “the serial killer just kills people for pleasure? Ok. Kinda cliché.” With maybe a bit of an eyeroll and an “oh, people with mental illnesses being demonized, how original.” And I mean, fair and valid. On his own, Saito isn’t that fun of a villain.
But here’s the thing that drives me a bit insane (affectionate) : Saito doesn’t exist on his own. He parallels a lot of other characters in ways that add a lot of depths to other characters & the themes of the game in general.
So, let’s look at those delicious delicious common roots!
Saito & Date: a matter of brains
So, quick question: why is Saito a serial killer?
“Because he gets pleasure from killing people, didn’t you read your own blurb?” Well, yes. But it isn’t as simple “everyone with brain dysfunctions is fated to become a dangerous murderer.” And the proof of that is Date. A guy who has the exact same brain dysfunction, but, hilariously, is also one of the only guys in this entire game who haven’t killed anyone.
You could argue that Date actually had medication to ward off the whole oxytocin deficiency. (It is a recurring this game that mental illness may be a bitch, but proper medication & a support system can go a long way to help.) However, there are two things to take into account:
1) Date still spent a whole year without medicine, and he still didn’t kill anyone.
2) Saito spent six years in a neurotypical body (it’s complicated) and it didn’t stop him from killing people, despite the fact that he no longer got any pleasure from it.
So clearly the issue isn't his brain. Why, then, did Saito end up killing people?
Saito & Falco: on the origins of evil
Then let’s look at the other serial killer of this game: Falco.
Falco’s motivations for killing people are very different. He doesn’t get any pleasure from it. He initially killed people for what he believed to be justice, and it snowballed from here. That being said, the narrative makes it very clear that murder is murder regardless of the circumstances; Saito himself points out that they’re not so different.
There is one other thing Saito and Falco have in common: their childhood fucking suck.
It’s mentioned in passing that Falco was raised in an orphanage and subjected to “every abuse imagineable.” Meanwhile, while Saito wasn’t outright abused, he was severely neglected- how else could he go twelve years without any medical treatment? What little we see of Saito’s relationship with his father is really strained at best.His father considered him abnormal and basically ignored him his whole life, only doing the bare minimum to stop Saito’s misdeeds from becoming public. Homeboy Saito suffered from debilitating isolation is my point.
“Okay,” I hear you say behind the screen, “but then why does Falco specifically get better, while Saito doesn’t?”
Well. Cheesy as it sounds: Falco chose love.
No, seriously! Falco got himself a girlfriend, a lovely daughter, and that prompted him to try to get out of the serial killing thing. It had mixed results, but he did try. Because no matter how many sins you’re wading through, it is never too late to choose to do good.
Meanwhile, Saito had a thousand opportunities to bail. He could have started over in Shouko’s body, with a perfectly healthy body and no crimes pinned to his name- he had an entire year to learn to make friends or discover the joy juggling or anything. He could have started over in Renju’s body and live a quiet successful life filled with cash. He could have started over at ANY point of time, and probably still have gotten away with it. Saito continuously chose to be a bitch, and that is what makes him truly evil.
Saito & Mizuki: what could have been
Mizuki Okiura, our protagonist’s roomie, also has a childhood that fucking sucks. Neglectful father (isn’t that familiar) and abusive mother, this poor girl was basically raised by Date, a man with more issues than vogue.
Now, I’m not gonna go into details regarding Mizuki’s abuse, but there is one bit that struck me when I was playing it: one of the words her mom uses to describe Mizuki is “abnormal.” I thought it was an oddly specific word- I expected the whole “my child is stupid and needy ect ect,” but abnormal? Who has that word in their day-to-day vocabulary?
And then it occurred to me. There is one other character who refers to their child with that word specifically. Saito’s father refers to him as such, and I don’t think it’s a coincidence that this man and Mizuki’s mother have a similar lexicon.
The similarities between Saito and Mizuki don’t end here. Saito killed his first human at twelve. Mizuki is twelve when the game starts. Saito gets pleasure from killing people. Mizuki is very obviously balling anytime she gets to fight, and the sequel shows that violence is her go-to solution for most problems.
“Okay,” I hear you say behind the screen, “but then why does Falco specifically get better, while Saito doesn’t?”
Here’s what I’m saying: Saito is what Mizuki would have become in a worst-case scenario. Mizuki is a Saito that was taken out of the cycle of abuse early enough. If Mizuki hadn’t met Date, she would have grown to use her strength to hurt people. If Saito had been taken in by literally anyone who gave a single fuck about him, he would have still grown prone to violence, but he would have had a good heart and would have learned to cope with it in better ways.
TL;DR
Saito isn’t just a random villain- he’s specifically a mirror of the worst of the other characters. He is the monster Mizuki could have become. He’s the creature Date used to be. He’s Falco one step removed. He’s equally a victim of his upbringing, and the actor of his own demise, as while he was certainly set up on the path of murder from the beginning, he chose to keep walking this way, as evidenced by other characters who chose differently. A lack of love would turn anyone to evil, but no matter what you have done, it is never too late to choose to do good.