NPC Theories

Black Haired Girls

  • It is postulated that these girls represent some kind of cancer, since they seem to collect in a fleshy area resembling the inside of a body.
  • It is also postulated that these girls represent Sabitsuki's immune system, since the point in the game that they start dying left and right is the same point that the little red creatures run amok and deal actual damage. It is speculated that the presence of the black-haired girls early in the game were preventing the little red creatures from exiting the mouth areas.

Cleaner (Gask Mask Maids)

  • Perhaps Sabitsuki's sickness was airborne (possibly due to coughing up blood and such) and her care takers may have had to wear these around her.

City Dwellers

  • Believed to represent Sabitsuki's view of city dwellers or people she doesn't know in general.

Demon Sabitsuki

  • It is possible that she represents Sabitsuki's weakened core.
    • Her noticeable resemblance to a red demon suggests she has been corrupted due to Rust's control over Sabitsuki.

Doctor and Nurse

  • They could be the staff that treated or interacted with Sabitsuki when she was in the hospital.
  • One theory suggests that Sabitsuki (or the Girl) became pregnant (by prostitution or otherwise) and that the doctor performed an unsafe abortion.

Girl in the Yellow Dress

  • Because Sabitsuki and the Girl in the Yellow Dress were seen drinking tea together, the Girl might be Sabitsuki's mother or sister.
  • Considering the amount of effort needed to reach either the hidden room in the Apartments or the Vomitgirl Area, it is highly probable that she holds some significance to Sabitsuki, though it's not too clear exactly what.
  • Seeing as how Sweet Sugar resembles the inside of a hotel, the girl standing at the edge of the statue could be synonymous to standing at the edge of a balcony.
    • She may be contemplating suicide, due to standing dangerously close to the edge of the statue (and the sad music playing). It can be assumed that she killed herself.
  • Because the Vomitgirl Area has obvious sexual imagery and subtle allusion to prostitution (through a love hotel), it can be inferred that the Girl may be a prostitute or was involved in prostitution somehow.
  • It is also possible that, due to the effort needed to see her and inability to interact with her, Sabitsuki tried to hide her in her mental landscape, or even forget about her (presumably after a traumatic/tragic event) .

Hospital Children

  • The children could be younger versions of the Kaibutsu and Sabitsuki, possibly meaning that they may have been in the same hospital together. Alternatively, they may be seen as children who underwent some sort of experiment like Sabitsuki had or may have been children with a similar illness.

Hovering Screens

  • The screens could represent when Sabitsuki was in the hospital that she was constantly under surveillance.

Kaibutsu

  • There is speculation that the Kaibutsu were people Sabitsuki knew either in the hospital or during her time in school.
  • The Kaibutsu could have been children with a similar disease to Sabitsuki and could have been test subjects to a cure which ended up with major consequences. The same type of cure could have been used on Sabitsuki with a longer wait till she becomes like them. It is thought this because as during the True Ending Sabitsuki can be heard giggling much like the Kaibutsu before she attacks the Gas Mask Maid.

Fetuses

  • Some theories state that these represent some type of disease that is plaguing Sabitsuki's body as they're originally only found in a certain part of the flesh wall world then begin to populate the rest of the worlds after the black haired girls start dying off in mass.
    • They also appear in heavy numbers during the final rust chapter. As the hospital corridors begin to rust you'll see more of them in each corridor.
    • Also there are two areas in the flesh walls world with the mouth background. One area has a relatively clean looking mouth and one red creature. The other has a bloody looking mouth and multiple red creatures. The increase in creatures may be a link to her coughing up blood.
  • Since they are called Fetuses, and initially can be found only in the world that resembles a womb, it is possible that Sabitsuki was, or is, pregnant. It is possible that this pregnancy was unwanted, since there is an area that implies prostitution, and this might be the reason why Sabitsuki sees Fetuses as demons.
    • Alternatively, Sabitsuki may be a child of a prostitute and was viewed as unwanted, or, if they represent her illness, Sabitsuki may be a child of a prostitute which was born unhealthy (due to STDs).
    • A similar theory, in line with hospital imagery and things associated, proposes that Sabitsuki (or the Girl/someone she knew) became pregnant (from prostitution/otherwise) and attempted to abort the pregnancy through unsafe means, like leading to a severe infection and organ damage.

School Children

  • Generally speculated to be children Sabitsuki and Smile went to school with or, rather, the latter's posse.