Gintsui no Alexandra

is a Japanese light novel series written by Yu Ueno, with illustrations by Iseno Yajin. The series began publication on November 10, 2007 by ASCII Media Works under their Dengeki Bunko publishing imprint.

Synopsis
One night, it was Sandra, a girl with a huge hammer, who saved Kosuke, who was seriously injured by a mysterious creature. In order to save Kosuke, she embeds "Magic Stone", which is the source of her magical power, in Kosuke's body. Sandra, who calls herself a wizard who has chased a "demon beast" that breaks through the "boundary of dimensions" from another "world," ends up in Kosuke's room with the shield of being a lifesaver. Kosuke is being swayed by Sandra, who has a big attitude and a strong appetite. Eventually, a demon beast appears in the city again, but Sandra's magic stone is still inside Kosuke's body, and she can't use magic! Kosuke challenges the demon beast to save Sandra.