Salacia Delorisista Amanita Trigestrata Zeldana Malifee (like all vampires who have a propensity for having long names, two more pages of names follows)...von Humpeding first appears in Thud! as a the new recruit on the Watch. She is the only vampire member of the Ankh-Morpork Watch, a Black Ribboner, a member of the Uberwald League of Temperance who has sworn off drinking blood and Vimes accepts her very reluctantly as, although he is a big supporter of inclusivity, he is not a fan of vampires. She joins the watch as a Lance Corporal (In The Science of Discworld IV: Judgment Day, she has moved up to Watch Captain although no mention of any intermediate steps is given in subsequent novels). There is a hint of a cheerful sexual promiscuity, possibly even bisexuality about her character. She is described as boyishly-built with short bobbed black hair, is 51 years old, but looks 16 and enjoys a drink and a laugh. She is also a cellist. She is trying to put a suffocating social system that offers little scope for amusement (Vampire society) behind her so has left Uberwald and moved to Ankh-Morpork. As well as her first name, there is much in common between her character and that of Berlin club singer and performer Sally Bowles, played by Liza Minelli in the film of Christopher Isherwood's Berlin memoir I am a Camera, (filmed as Cabaret). Sally's last name has similarities to Engelbert Humperdinck the well know British singer, with all the sexual connotations the name implies. Her name has a number of references to Roundworld. Amanita is a type of poisonous mushroom. Malifee has connotations of bad/evil (the meaning of mal in French).
Like most vampires in Roundworld and Discworld she is under the misguided belief that signing her name backwards on secret messages is a clever disguise as to her real identity. Near the end of Thud! Vimes uses this naivety to discover that she is actually a spy for the Dwarf Low King but he keeps her on his staff in spite of this.