Kasane Shibata

Kasane, a survivor of the Shishigou incident, is Asumi's childhood friend. Because of the crash, she has a horrible burn mark on her left arm. In the present, Kasane goes to an all-girls school. In the manga, her first reappearance shows her sleeping in Asumi's dorm room, which is a few volumes after her reappearance in the anime.

(Source: Wikipedia)