Rika Konno
About
It is suggested Konno loses her eye in the bus crash.
Konno becomes very jealous and paranoid while she is barred from working, and takes information Mitomo gives her as truth. The information leads her to believe Sanada and Amano had something to do with the crash and the murders---and by proxy, the injuries that make her unable to work---and attempts to kill them in revenge/retribution.
She later finds out the information was false, and in the 'bonus chapter' she stabs Mitomo.