"That's kind of a cute thing of you to say, but being too cute has its drawbacks too."
Saki Enomoto is a character that did not appear in Katawa Shoujo, but rather on the blog as an April Fools joke, along with Rika Katayama. She has spinocerebellar ataxia, a degenerative disease that makes her lose muscle control, and will eventually kill her, but this has not stopped her from living her life to the fullest. The blog post she debuted in treated her as an additional girl that Hisao can pursue in an "expansion story."
Though no name is given, there is a girl member of the Art club that you can see in the art room's image during Rin's route, who looks just like her and according to her character information from the April Fools joke, Hisao first meets Saki there.