Signum is the leader of the Wolkenritter group. She first appears on the series Magical Girl Lyrical Nanoha A's.
Signum is a creation of the Book of Darkness (Yami no Shou) n is generally seen as the cold-hearted one but her companion Shamal pointed out that Signum's heart has warmed since they met their new master Yagami Hayate. Signum's weapon is a chain- link sword called Laevatein. Signum is a person who respects the strength of others and does not underestimate them. She is kind and soft-hearted, but she only started smiling after meeting her new mistress Hayate who treated her and the Wolkenreiter like family instead of tools to collect pages for the book of darkness.
Signum also appears in the next installment of the nNanoha series that is Magical Girl Lyrical Nanoha Strikers. In this series, Signum is the sub- commander of the lightning squad of the TSAB Ground Forces Riot 6. Although a sub-commander is supposed to help train the new forward team of Riot 6, she does not do so on the excuse that she is an old fashioned knight and does not have much to teach back-ups like Teana and Caro much less Erio and Subaru who are Neo-Belkan users with some Mid-Childan magic mixed in.
Though on one occasion she accepted Erio's request to spar with him. During the series she also meets unison device Agito who fights alongside with former knight (who was supposedly killed 8 years ago) Zest Grandweitz. Signum fought with him to prevent him from entering the Ground Forces HQ and with her was a unison device Reinforce Zwei. The first round came out to a draw, but when the fight was resumed in the Ground Forces HQ Signum came out victorious. In his dying breath, Zest made Signum promise to take care of Agito and Lutecia Alphino.
Signum's official birth date is during the ancient belkan era, officially 0046 years.