Lain's older sister, an apathetic 16-year-old student who casually picks on her little sister's habits and behavior. Mika is considered to be the only normal member of Lain's family; she sees her boyfriend in love hotels, is on a diet, and shops in Shibuya.

At a certain point in the series, her consciousness is seriously damaged by violent hallucinations. While Lain begins freely delving into the Wired, Mika is taken there by her proximity to Lain and gets stuck between the physical world and the Wired.
(Source: Wikipedia)