Signum's weapon is a chain-link whip sword called Laevatein, and as a magical creation, she has no familiar. She is named for the Opel Signum, much like characters of Magical Girl Lyrical Nanoha are named for cars, and her device appears to be named after the mythical sword Laevateinn. As per the other Wolkenritter, she has no last name.
She is voiced by Shimizu Kaori (Japanese) and Bailey Chadwick (English).