Why does Fuminori see his own body as normal? The only thing I can think of is that his body sense overrides whatever is affecting his perception of the rest of the world.
Perhaps it's denial? He sees himself as a monster (which would give another reason explaining why he's so full of self loathing) but he pretends that he sees himself normal to not freak Saya out. That or his condition doesn't affect how he sees himself, for whatever reason.
I'd think that it is his sense of self. The whole thing is mental, afterall.
Or maybe he got so used to seeing everything reversed that he had started seeing himself as a monster, and thus appearing human-like to his own eyes.
Considering he's sexually attracted to a little girl, and how in all the routes but the one with the least amount of bloodshed and suffering (ie, he chooses to become normal again, which is pretty clearly presented a Non Standard Game Over and not a true ending) he's generally cool with killing what he knows are innocent people and eating the flesh of children, I'd say he was a monster and therefore able to see himself normally.
Moralizing aside, that wouldn't actually make sense. Even if he's a monster, he's still physically a normal human.
Why should that make a difference? All the other characters that Fuminori interacts with besides Saya are actually decent-hearted people, and when Saya messes Yosuke up, he instantly becomes a pedophile rapist. It's an Alternative Character Interpretation but it does imply that Fuminori sees normal people as monsters and monsters as normal people, including himself.
Because he would go insane almost instantly and we would not have story, duh.
It can be argued he was already insane and we had this story because of it.
At one point, Fuminori explains that his senses were fine until he recovered his eyes. His brain then altered his other senses as a form of adaptation to what his eyes were seeing. It is never told directly but one could reason that some of his senses such as "proprioception" (the ability of knowing your own body and its position) didn't adapt due to being stronger than his sense of sight.
Proprioception, unlike his other senses which were affected, is largely subconcious.His visceroception probably wasn't affected either.
Sorta begs the question why he didn't just wear a blindfold, then. If he perceived everything normally until he started being able to see and his other senses warped to go with it, then the simple solution would be to just live blind.
What's puzzling is how the tentacled Eldritch Abomination Saya is able to overpower other humans, but was helpless when she was raped by an insane Yousuke.
Anytime she attacked a human, she had 2 advantages, surprise, and the fact that they were looking at a whatever she was. With Yusuke she had neither of those.
That's still pushing it, I think. She's nigh-impossible to kill or damage and Yousuke had been a very docile person up to that point, it's not like he was a secret agent with combat training. Saya really shouldn't have needed much advantage over him, considering how hard the ending fight is.
I think what's puzzling about that is how she couldn't get away at that point. She's a squishy, blobby tentacle thing. Even if you're willing to assume that.. uh, she has all the necessary orifices in a way that would be analogous to a human, how does anybody actually manage to hold onto her?
Why didn't Fuminori attack Kouji while he was distracted by Yoh? He was firing the gun for a while after it went click, then hitting her for a long time afterward, yet Fuminori only came in after Kouji wasn't too scared or loud to notice him. If Yoh was still "alive" after he killed Kouji, Ryouko might have mistaken Yoh for Saya and wasted her chance.
Perhaps at that point in time, Fuminori was at his most sadistic and insane. Given the way he mentions how Yoh just met her demise, he might want an even bigger psychological edge over Kouji, and that would seemingly come perfect in the guise of, "That thing you just killed was Yoh, you monster." Approaching him while he was still engaged with Yoh might've triggered a flight response from him either way, and if he ran and had time to recover, Fuminori wouldn't have been able to finish him off. He wanted to root Kouji to the battlefield, lessen the risk of him fleeing due to Yoh's involvement, but at the same time be broken enough to not be at full fighting capacity while giving Fuminori, the weaker of the two, the biggest psychological advantage, perhaps even an emotional one given that Kouji just killed the only other girl he now saw as normal and part of his family, which Fuminori could use as emotional drive to propel his adrenaline and lust for Kouji's blood. Not that it works out completely, but given the state of mind Fuminori was at the time, it might've seemed the most logical thing to do. After all, if Kouji saw Yoh and then, knowing he was about to be engaged by Fuminori while this THING was boring a hole into his sanity, ran off, he might get anyone else involved in a matter of minutes, which put Fuminori and Saya at risk of being discovered, which was what Fuminori had as about equal priority to killing Kouji. Without Yoh being in a safe, human form and proven to be alive and unharmed, Kouji could have easily made things impossibly harder for the new Sakisaka family. Also remember that, while Fuminori isn't exactly sane, he still views the world as a disgusting horror and, if far enough away so as not to be at risk from being detected by Kouji before Kouji could be engaged by Yoh, he has to gather his nerves and navigate to the room they're in. At this point in the novel, the story doesn't play up how affected Fuminori is by the fact that he still senses himself as alive in his own little wretched world, but I think it's a safe assumption that, while his will to live and try to enjoy life has improved since the beginning of the story, he is still living in a world that he's had issues dealinsoig with trying to both navigate and not be nauseous just existing in.
The H scenes. Considering Fuminori's condition, wouldn't the pleasure of normal sex amount to excruciating pain for him? Unless you want to take into account that since Saya is an Eldritch Abomination, the kind of sex he's been receiving from both her and Yoh is probably the equivalent of having your member near mutilated beyond normal human levels of pain tolerance. Or is sexual pleasure exempt from the whole brain condition thing?
I think the whole brain condition thing is the very reason he's able to enjoy his sex with Saya. If you look at the way he perceives his former friends after the accident, it's abundantly clear that he'd never be able to have sex with any of them ever again. I think that after the accident happened, he'd actually changed in more ways than just his perception. He'd pretty much become like Saya once his gorn-o-vision set in. I don't think he was human anymore, especially when it comes to his sexuality and eating preferences.
So Fuminori's mental condition. The framing device of the story and a massively important plot detail. Was it just a massive coincidence that he happened to suffer from an never heard before illness that made him compatible with Eldritch Abominations? I was expecting it to be revealed at some point that Saya or Oughi were behind it but as far as I can see the cause of it is never addressed beyond the accident. Which makes Saya's species seem to suck at their job since she got super lucky there was something able to breed with her via massive coincidence.
Not really. Saya is sexually compatible with humans regardless of how they see her, they just obviously wouldn't want to because literally no sane person would get near that. The coincidence just makes it possible for her to have consensual sex with a human. Otherwise she'd have to rape some poor, sad person to get the DNA samples she needs.
So what exactly did Tanbo see that drove her so over the edge? She repeatedly says she wishes she had a gun a year ago and that she could have ended it all back then which made this troper assume she had had some form of run in with Saya but the final ending her inner monologue says she never met Saya. Was it just a couple of mutated rats that gave her repeated nightmares to the extent she stole and illegally modified her father's gun? Apart from that comment it makes sense she's seen Saya before given her parallels with Kouji in the other ending and her own seeming lack of reaction upon seeing Saya in that ending. Plus her general zealous willingness to kill Saya.
She's most likely referring to Ougai, not Saya. She could have killed him, but didn't for whatever reason.
How does Yousuke end up seeing Saya the same way Fuminori does? Yeah, they have the same brain disorder that makes the world appear disgusting, so that at least makes a certain amount of sense, but how can Saya look the same way every time to two different people if her appearance is entirely a hallucination? And why does she appear to be wearing clothes? Is the reason looking at her makes normals go insane because they're looking at an eldritch abomination wearing a sundress?