Red Demons are creatures which like the Kaibutsu will chase Sabitsuki often running very fast after you.
They appear as red impish things with teeth where there face and stomach should be, and possibly antennas or horns.
From the start of the game up until you drop all your effects they can only be found in the Flesh Walls World and only in one quarantined area ( Deranged Mouth World ). However, after shedding your effects and becoming Rust you'll see them everywhere, oftentimes where a Kaibutsu use to be but other times in areas nothing was before.
- Contact with one of these creatures as Sabitsuki will cause whatever effect you have on to be canceled, but if you run into one of these creatures as Rust you'll begin seeing her become damaged every so slowly with ever creature that attacks you. This will continue until Rust's head literally explodes she wakes up.
- In v0.15 they not only materialize out of pools of blood in Rust's Corrupted School event but they also replace the Kaibutsu.
- They consequently are much larger than the normal ones. Also, for some reason, they are harmless, but this is due to a bug explained here.
- 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 dieing 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.