Misuzu Misaka is Misaka Mikoto's mother, first appeared in volume 9 and again in volume 10, Volume SS and Volume SS2. Currently studying at a university. Mikoto often comments her mother acts more like a child than she herself does. Misuzu is very weak to alcohol, and after getting drunk she has a habit of clinging to a young guy she finds attractive.

(Source: Toaru Majutsu no Index Wiki)