Rust

Rust is a playable character after collecting all 25 effects, and then going into flow while in flow. All you have to do is examine you computer while in flow. Rust looks a lot like Sabitsuki, but with one difference. Her hair and clothes are more detailed. She can do many of the things Sabitsuki can, but can not collect effects. However, rust can access three areas where you were not allowed to enter. There are more red demons when you play as rust- in areas where Kibutsu have previously been, or new areas.

Trivia

 * Rust is actually a red demon. You can see this if she gets hit by too many.

Theories

 * Rust may have been the diseased part of Sabitsuki