The main character. A medical student in his twenties and the sole survivor of a horrible car accident. Saved by an experimental medical treatment, he now sees the world in a contorted manner with the exception of one thing: a girl named Saya.
Ax-Crazy: He even buys an ax later on to use for the specific purpose of hacking apart one of his former friends.
Cannot Spit It Out: He won't tell anyone about his agnosia, for fear of becoming a guinea pig in lab experiments. Naturally, his silence ends up doing more harm than good.
Conveniently an Orphan: The fact that both his parents were killed in the horrific car crash means no one really knows what's going on inside his house.
Driven to Suicide: Attempted it before the beginning of the game due to his condition, but didn't succeed. Succeeds in 1 of the 3 endings in a particularly gory way, by smashing his face repeatedly into the blade of an ax.
Non-Action Guy: Kouji is a much better fighter than him because of this, and nearly beats him in their final duel before Saya intervenes.
Not Good with People: In a sense. After losing his normal senses of perception, he can only relate well with Saya, who's actually an alien, and not with other people since they look like monsters to him.
Parental Abandonment: Both his parents were killed in a horrific car crash that led him to his medical illness.
Yandere: His reaction to finding someone raping Saya was to take the nearest meat cleaver and go crazy hacking at the man with it. He is also willing to let the world be damned for the sake of their love.
Brown Note: Her true form is treated like this. All of the humans that have seen it have immediately lost their sanity if they aren't outright killed by her. Only people who are already insane/disturbed seem to be unaffected, not to mention people with Fuminori's brain disorder.
Ceiling Cling: Capable of doing this to sneak up on her prey, and she kills Ōmi this way.
Does Not Like Shoes: It seems so, but the player doesn't see her feet when Fuminori talks to her, unless the CGs show more of her body. She's mostly seen in his house where she doesn't wear shoes (or socks). It's probable that she doesn't have shoes, every other character who enters in Fuminori's home doesn't see shoes of a girl. However, when Yousuke can see her as a normal girl, she's seen wearing white sandals.
She also wears sandals on the cover.
Don't Look at Me!: In the first ending, she visits Fuminori in the mental ward at night one day, but refuses to let him see her true form despite his desire to see her one more time. Instead, she passes him a cellphone from behind the door which they use to exchange messages with each other, until she finally bids him farewell.
Eats Babies: Maybe. Supposedly one disappeared from the hospital while Saya was staying there, but nothing is confirmed.
I'm a Humanitarian: Technically, although she only counts as one because she looks like a human in front of Fuminori while eating her favorite kind of meal.
To Serve Man: She can eat animals as well, such as birds or cats, but prefers humans above all else.
It Amused Me: She used to haunt the hospital Ougai worked in prior to meeting Fuminori, and spent her nights wandering the halls and scaring the crap out of insane patients (who would never be believed by anyone) for her own amusement. In fact, this was the reason she met Fuminori in the first place since she was trying to terrify him with her appearance, but when he didn't react to her with fear, she became interested in him.
I Want My Beloved to Be Happy: In the first ending when she returns Fuminori's sight to normal again, while knowing that he can never love her the same way as he did before.
Kill It with Ice: In the third ending, Saya gets killed with the help of liquid nitrogen after Ryouko discovers the only vulnerability in her biological makeup: below freezing temperatures.
Leitmotif: Song of Saya I & II, two soothing but distinctly otherworldly and eerie tracks that capture everything about her character perfectly.
Living Emotional Crutch: So very much for Fuminori. If he had never met her, he would have killed himself a long time ago. In fact, one of the three endings has him commit suicide immediately after seeing her dying body.
Rapunzel Hair: Goes all the way down her waist to her feet. She has two shorter locks of hair that stick out rather like cat ears, too.
Rasputinian Death: In the third ending. Even after getting half her body frozen by liquid nitrogen and then blown off by a 12-gauge shotgun, she somehow manages to slowly crawl over to Fuminori's side, all while Kouji is bashing her body over and over with a steel pipe, until she finally reaches him, weakly touches his face and then finally dies.
Star-Crossed Lovers: With Fuminori. The only ending where they both survive is the one where he's locked up in a mental institution for the rest of his life, and she's out there somewhere still searching for her foster father, Ougai.
Combat Pragmatist: His skill and experience in street fighting makes him a superior combatant to Fuminori, who has never fought anyone before.
Driven to Suicide: In the third ending. He hasn't killed himself yet, but the only way he can continue living with the knowledge he now has is by keeping a revolver loaded with a single bullet in his room all the time.
Horrible Judge of Character: Justified in that Fuminori was his best friend though, and Kouji would have never guessed he would later try to kill him. Nonetheless, he still suffers a bit from this when Fuminori shows up, starts acting strange, and abruptly asks to be driven all the way to a far, remote location without suspecting he might be up to something.
The Insomniac: Suffers from recurrent nightmares after surviving in the third ending.
The Match Maker: He and Ōmi were trying to get their respective friends, Fuminori and Yoh, together as a couple before the accident happened.
Nice Guy: He's the only genuine example of this, unlike Fuminori, at least before he gets broken down by his subsequent experiences.
Only Sane Man: Lampshades this at one point, when he wonders why he keeps meeting crazy people all the time. This is before he loses it too, though.
Pipe Pain: He picks up a steel pipe during his final confrontation with Fuminori at his new home.
Spanner in the Works: If he hadn't called Ryuko when Fuminori wasn't looking, he would've been left to die in the well and Fuminori would've gotten away with everything with nobody to stop him.
A Tragedy of Impulsiveness/Too Dumb to Live: The player can actually invoke these tropes by choosing to have Kouji immediately phone Fuminori after finding the refrigerated remains of his girlfriend in Fuminori's house, rather than choosing the more rational option of contacting Ryoko first. Depending on which choice is picked, Kouji will either play these tropes entirely straight or avert them.
Stuffed In A Fridge: Literally. Her boyfriend discovers her grisly remains (including what looks like her dismembered hand) in one of the storage containers in Fuminori's refrigerator.
Too Dumb to Live: Hearing a strange voices in Fuminori's home, yet, she still doesn't leave it.
Voiced by: Mio Yasuda (credited as Izumi Yazawa)
A young woman with an unrequited crush on Fuminori. She sincerely tries to help and understand him but her attempts to reach out to him are always met with disdain. She dies in 2 of the game's 3 endings.
Body Horror/Viral Transformation: Happens while she is slowly and painfully getting transformed into the same being as Saya. When Kouji phones her, she says that her ear is melting off, and her fingers aren't supposed to look like that...
There Is No Kill Like Overkill: First she gets shot four times, and then she gets beaten to a bloody pulp by Kouji's steel pipe when he freaks out after seeing her transformed state. The text states that she stopped moving after the twentieth time he used the pipe, but he keeps going all the way past thirty.
Too Dumb to Live: She knows that the one who sends her mails on her mobile phone is not Omi, but she still goes into Fuminori's house. Even when she hears the strange noises and is horrified, she wants to believe that her friend might prank her. Saya doesn't kill her, but Yoh's transformation into an Eldritch Abomination ultimately leads her to her death by Kouji.
Fuminori's doctor. A friendly professional who wants to help Fuminori as best as she can. Her real personality is actually very distant and calculated. She also knows a lot more about Fuminori's condition and treatment than she lets on. She dies in 1 of the game's 3 endings.
Beneath the Mask: On the job, she's a kind, friendly doctor, albeit somewhat cold and extremely secretive. Off the job, she's paranoid and obsessed with killing the Eldritch Abomination that haunts her dreams.
Dying Moment of Awesome: Despite getting an axe cutting down through her left shoulder to her chest, she manages to point her 12-gauge shotgun at Saya, who has been partially frozen by liquid nitrogen, and pull the trigger in her final moments, all while smiling horribly.
Psychotic Smirk: Flashes these several times to show her breaking sanity, but most triumphantly when she pulls the trigger of her shotgun in her final moments to finish off Saya while sneering at Fuminori.
You Gotta Have Green Hair: Oddly, she's the only major character with an unrealistic hair colour, besides Saya whose human appearance isn't her true form, at any rate.
Click here to see the picture
Doctor Masahiko Ōgai is the foster father of Saya and he worked in Dr. Tanbo's hospital, until he suddenly disappeared. He's involved in several mysteries and Fuminori helps Saya to find him and he investigates him. Dr. Ōgai studied Saya and taught her various things, e.g. talking or math. He commited suicide, and his skeleton is found by Doctor Tanbo and Kouji if the player doesn't play the first ending.
Bigger Bad: He kept Saya in his home where she developded her personality.
Fuminori's neighbor and an artist who lives with his wife and little daughter Hiromi next to the Sakisaka house. Saya messes with his brain, giving him the same vision problem as Fuminori. Believing that his wife and daughter are aliens, he kills them and then he rapes Saya, believing she's the only girl in the world. He's killed by Fuminori during his rape.
Neat Freak: The game goes into great detail about his daily routine and how obsessive he is over keeping his house clean.
Nice Guy: Played with. He offers his help cleaning Fuminori's garden since it's stinking, but Fuminori suggests that he pretends to be nice and Fuminori's garden disturbs Yousuke's perfect image of his house. However, Yousuke talks with his wife about Fuminori's current situation and they seem to concern about him. Then Yousuke goes insane and he loses his nice attitude anyway.