Sabitsuki (さびつき Sabitsuki ) is the main character of .flow, controlled by the player. She is a mysterious, seemingly ill girl secluded in her bedroom, with nothing to do but play Shinsoku Neko or enter flow in search of 24 effects.
After collecting and dropping all 24 effects, Sabitsuki is replaced as the player character by Rust.
Sabitsuki is a girl with short shaggy white hair. Her default outfit is a faded purple-grey shirt with no sleeves, a white skirt, and red or purple shoes, but her different effects will alter her appearance and outfit in different ways. Sabitsuki's mouth is only visible during select events, and her eyes are always closed. She seems to be a teenager, going by illustrations by lolrust.
- Sabitsuki's name continues the tradition of giving fangame characters a name ending in -tsuki. However, the kanji in Sabitsuki's name have a different meaning than the ones in Madotsuki's name. Sabitsuki means "covered in rust".
- According to the equipment screen, the skirt she wears is her favorite one.
- When asked about Sabitsuki's orientation by a fan, lol answered that "She does not understand "love" so much". This could possibly allude to her being aromantic or on the aromantic spectrum.
- It is likely that the shape on the title screen of .flow is a very abstract depiction of Sabitsuki herself.
- It is theorized that Sabitsuki is slowly losing her mind either from the disease or from side effect of her treatments.
- The Kaibutsu also seem to have lost their mind as well (active chasing ones) or are on the verge of losing them (normal ones that will become active after hitting) which could further link that both Sabitsuki and the Kaibutsu are suffering the same disease/side effects from disease treatments.
- Sabitsuki possibly didn't fit in much at school and was either widely ignored or made fun of. Support for this theory comes from that going through the Corrupted School Kaibutsu will actively chase you with pipes as their laughter fills the halls.
- It is possible that Sabitsuki is being quarantined due to the disease she has.
- It is possible that Sabitsuki suffers from albinism, given how she has pale skin and white hair. It could be that this caused her to be bullied at a young age, due to her looking drastically different to the other students and teachers.