Index is one of the main heroines and the titular character of A Certain Magical Index. She is a young nun from Necessarius, a branch of the Church of England. Index is small in stature and has a petite build. She has thigh-length, silvery-blue hair with very white skin and large green eyes. She also wears a white robe with golden embroidery sewed onto every edge of it, the Walking Church, that prevents any injury on her.