Mika Iwakura is a supporting character in the anime series 'Serial Experiments Lain.' She is the older sister of the protagonist, Lain Iwakura. Mika is depicted as a typical high school student who is often detached from her family and wrapped up in her own social life. As the series progresses, Mika becomes increasingly unsettled by the strange events surrounding Lain and is deeply affected by the family's growing dysfunction, highlighting the emotional impact of Lain's transformation.