The entire manga is in Satou's mind.
While a cliché idea, this does explain a few aspects of the world like how nearly every other character introduced is a deeply disturbed individual, but considerably worse than Satou herself. It could also make some sense to believe that Satou may have only initially seen Shio in a missing person report and latched onto her creating a life where she was convinced that she was in love with her and that all of the conflict in the manga is simply a figment of her mental unstableness. Asahi and Shio's father is now a Corrupted Soul.
His current looks
◊ strongly hint towards it and even if he was an asshole while still alive, dying didn't make him a better person a single bit. I just hope Dale Vandermeer takes care of him ASAP. Satou will die.
The manga/anime make it clear that no matter how pathetic Satou's upbringing was, there is the likelihood that she would be too far gone for rehabilitation. The only way I could possibly see Satou dying is either from the events of the first episode where she and Shio are about to jump off the building, or Asahi would be forced to kill her, especially when he figures out that she killed Shouko. Or — alternatively— everyone dies.
Naturally a dark series such as Happy Sugar Life can only end with no resolutions for any of the characters involved.1) Satou and Shio die together after jumping off the building.
2) Mitsuboshi either dies in a scuffle with Satou or maybe from suicide given how Satou’s Aunt was forcing herself on him. Given his traumatic experience with his original boss, the latter is more likely.
3) Asahi would die in his confrontation with Satou. Maybe Asahi gets to finally see Shio again before meeting his untimely end.
4) Satou's Aunt could end up getting murdered by Mitsuboshi in self-defense. Whether she ends the series killed or alive and badly injured, she probably wouldn't care regardless. She might end up getting killed during when she is Incarcerated by a inmate.
5) Daichi could try to exploit Satou again only to be merked by her.
6) Yunna could possibly succumb to the poison.
7) The Manger possibly ended up killing herself after her defeat.
Shio doesn't exist.
A recent interpretation of the anime and manga series suggests that Shio may not actually be a real character at all. Rather, she represents pureness which is the main motivator for characters such as Mitsuboshi and Satou being obsessed with her. Asahi compares Shio to the moon, which in folklore is known to be associated with driving people insane. Hence the term "lunacy." Shio has Dissociative Identity Disorder (DID).
Shio has Dissociative Identity Disorder (DID) or some other dissociative disorder. DID is formed by severe, repeated trauma occurring in childhood before the age of around 6-9, the age where your brain develops an identity and personality. This trauma prevents the brain from properly integrating one cohesive identity, instead creating multiple parts separated by amnesiac barriers. This is often a coping mechanism to protect the child from having to deal with such severe trauma, so they can function normally in their everyday life. Other criteria include a lack of secure parental attachment and an ability to dissociate to high levels.
- Shio is eight years old at the time of the story, and has experienced severe, repeated trauma at home her whole life. Having an abusive father, a mentally unstable mother who turns to abusive behaviors, her mother poisoning her father and then killing herself, being abandoned and then kidnapped by a psychotic, possessive, violent teenager who keeps her locked up and isolated the whole day fits the criteria for severe, repeated childhood trauma without any room for disagreement.
- Having an abusive father and an extremely unstable and abusive mother satisfies the criteria for lack of secure parental attachment.
- Now that both of them are dead, that doesn't exactly help the case for secure parental attachment either.
- When meeting Taiyou, Shio seems to have no recollection of her family. Up until this point, she seems to have no recollection of anything prior to her living with Satou. This could be an amnesiac barrier created by dissociation to protect Shio. All these memories are painful, traumatic, and could make her feel unsafe. Her brain seems to recognize that a desire to leave could put Shio in danger because it would make Satou angry with her. After all, with Satou, she has food, a roof over her head, and she's more or less safe from the outside dangers that her parents aren't there to protect her from. When she does go outside, she's met with danger and fear. Even if Satou is a psychotic girl who's kidnapped her, she's caring for Shio and keeping her safer than anyone else has so far. So remembering that she has a family out there who might be looking out there may compromise her safety with Satou. It's easy to see why her brain would create this amnesiac barrier.
- The times where Shio "hallucinates" her mother being there seem much more like dissociation. The scene where her mother places her hand on Shio's and guides her to open the front door and go outside seem less like a hallucination and more like someone else other than Shio is performing these actions. It's common for those with dissociative disorders like DID to feel as if they're losing control over their own bodies, or as if someone else is moving their body and speaking through them. The fact that the hand turning the knob is disembodied from Shio just makes it feel even more accurate.
- When Satou comes home and finds Shio laying on the ground, unresponsive, stuck in her own head, Shio is definitely dissociating. If she were having a normal panic attack, she'd be reacting in some way to her surroundings. Shaking, crying, and probably noticing when Satou found her. Instead, she lay completely still on the ground and having absolutely no awareness of what's going on around her, to the point where she can't even recognize that Satou has come home and is right there next to her. She seems to have no recollection of these dissociative episodes.
- At the end, after Satou's death, we see Shio in the hospital behaving in a way that's uncomfortably similar to Satou, speaking as if she is Satou, saying the famous "I've been reborn" line. This could very well be an alter of Satou. It's actually quite common for systems to develop factive alters of those they were close to after experiencing the trauma of losing them. For someone like Shio who has dealt with dissociation, abandonment, and trauma more times than any girl her age should have to, this is a very natural way to cope with loss.
- This is also consistent with Shio forming an alter of her mother, as discussed previously, after experiencing the trauma of being abandoned by her.
- Also, at the end we see that quite some time has passed since Satou's death when Asahi visits Shio in the hospital. Why has she been there so long? She seems to have recovered from all major injuries. No bruises, no burns, no problems with her neck, back or arms...and yet still has bandages to cover up what are probably some minor scratches on her face. Which means that quite a bit of time has passed, and that those scratches are fairly recent. Perhaps this is actually a mental facility she's in, because she's extremely unstable and has no one who can support her. That would explain a lot about the situation.
- Why would she also have a gown and an IV, you ask? Same reason she has cuts on her face: She either got into an altercation with someone else OR ended up hurting herself while having a trauma response. As someone who's been in facilities like this and suffered in similar ways to Shio, this troper knows it's pretty common to have outbursts that end up causing physical damage to yourself. Especially when you're so young that you lack the emotional regulation skills, and also dissociate so highly you may not be aware of it until later. The IV fluids were most likely for sedation and pain relief. And if you have to be sent into a medical ward within a mental facility, much of the time they will still put you in a gown.
