Erica Hartmann is a witch of the 501st Joint Fighter Wing, originating from Karlsland, and affiliated with the Karlsland Air Force and her home unit: the JG 52. She is the twin older sister of Ursula Hartmann, a scientist. She is also Gertrud Barkhorn's closest friend. Erica often complains about orders that Gertrud Barkhorn gives her and receives endless lectures because of it but when there is a Neuroi attack she instantly forgets about being lazy and fights for humanity. 