- "Disguise and subterfuge are their meat and drink. They are assassins, spies of the highest order. No one knows who they are. No one has ever seen their faces and lived. They come to us masked if they mean us no harm. Masked in the manner of Venice when the rich and powerful wore masks, caps, and hats, so all looked alike, and none could be distinguished from the other. If they appear before us in those costumes, then they are merely here to observe. If they appear in the masks of their namesakes, then it could go either way. They could be merely observing, or they could mean to kill us. They would wear their namesakes, both to hide their faces and to let us know that if we do not cooperate they could turn deadly."
The Harlequin or The Nameless Vampire Guards are the closest thing to police that vampires in the Anita Blake universe have, and were created by the Mother of All Darkness, modeled in style on the Commedia dell'arte. There are four masks that each member must wear to conceal their identity:
- White - Observation
- Red - Pain, punishment
- Black - Death
- White with little gold musical notes - They wish to meet, not torment or kill, but to talk
They are based on the myths of the wild hunt and were established to control the vampires. It is composed of very old and powerful vampires who are capable of not just manipulating the behaviors and emotions of humans or younger vampires and lycanthropes, but even master vampires, or alpha weres. They owe allegiance to no one line, can fly and punish the wicked and kill mysteriously and quickly.
Their names are: Harlequin, Punchinello, Scaramouch, Pierrot/Pierrette, Columbine, Hanswurst, Il Dottore.
Once a member dies, their name and mask are supposed to be retired.
Mentioning the name Harlequin without being contacted by them first is cause for death sentence, until Jean-Claude inherits them after Marmee Noir's death and changes the rule.
After the Mother of all Darkness killed the last High Queen of the Yellow Clan, she permitted the Harlequin to keep their yellow tigers as their animals to call, but continued to hunt the Yellow Clan to extinction. Secretly some of the Harlequin spared some of the yellow tigers and hid them from Marmee Noir, breeding the bloodline until the day they put the Darkness back to sleep.
One thousand years ago the Harlequin used a spell, a sacrifice of lives and the power of the yellow tigers to bind Marmee Noir to her latest inhabited body and to put her to sleep. Although they intended to kill her, they couldn't figure out how to do that.
After Marmee Noir was put to sleep the Harlequin continued to do their job, but some started to work as assassins for members of the Vampire Council. When Marmee Noir started waking up from her sleep, Pantalone, Columbine and other rogue Harlequin came to St. Louis with the intention of taking it over. They were stopped and killed by Anita, Jean-Claude and their people.
After the body of the Mother of all Darkness was destroyed, and she possessed some of the Council members, a civil war started between the members of the Harlequin that still served her and those that wanted her dead. (Bullet)
- Mischa - A Master Vampire who followed Jean-Claude after Anita killed the dark mother.
- Pantalone (former Pantaleon) - Leader of the rogue Harlequin. He, Nivia and Mercia took assassination jobs from council members. Fearing the return of Mermee Noir he tries to kill Jean-Claude, Anita and Richard and become the master of the city of St. Louis. He was both vampire and werewolf (and ancient wolf) and could control the darkness and hide inside it. (Deceased)
- Columbine - She tries to "steal" the congregation of the Church of Eternal Life. She could create and feed on doubt. (Deceased)
- George - A red weretiger one of the Harlequin that kidnapped Anita in Hit List. (Deceased)
- Giovanni - The human servant of Columbine. (Deceased)
- Nilda (Brunhilda) - a werebear from an extinct species of red bear. Was being abused by her Master Gunnar.
- Marius - Nicknamed Harley by Anita. A wereleopard and one of the Harlequins that kidnapped Anita in Hit List. (Deceased)
- Mercia (Deceased)
- Jane - a vampire and the Master of Seamus.
- Goran - a werebear and the animal to call of Mischa.
- Nivia - A vampire that tried to turn Anita, Jean-Claude and Richard against each other. (Deceased)
- Jake - Werewolf that protects Anita when she is mentally attacked by the Harlequin. He reveals himself to be one of them and that he came to investigate the activities of the rogue Harlequin.
- Seamus - a werehyena of African origin and the animal to call of Jane. Nicknamed "Dark Water" by some of the guards
- Unnamed vampire - Master of George. Beheaded while he slept so George would die. (Deceased)
- Unnamed vampire - Master of Marcus. Beheaded while he slept so Marcus would die. (Deceased)
- Unnamed vampire - Master of unnamed wereleopard. Beheaded while he slept so his animal to call would die. (Deceased)
- Unnamed shapeshifter - Burned alive. (Deceased)
- Unnamed wereleopard - One of the Harlequin that kidnapped Anita in Hit List. Died after her master was beheaded. (Deceased)
- Yiyú's master - A black vampire, and the former master of the black weretiger Yiyú. He sent Yiyú to spy on Anita and Jean-Claude during their meeting with the weretigers. (Deceased)
- Sebastian - A black weretiger, he was Vittorio's tiger to call, and after his master lost his powers became a Harlequin.
- Soledad - A golden weretiger, she was Nivia's animal to call. (Deceased)
- Thaddeus - A werewolf and one of the Harlequin that kidnapped Anita in Hit List. Sacrificed himself to save Lisandro. (Deceased)
- Thing one - A werelion male and one of the Harlequin that kidnapped Anita in Hit List.
- Thing two a.k.a. Magda - A werelion female and one of the Harlequin that kidnapped Anita in Hit List.
- Topaz - A golden weretiger who comes to St. Louis to see if Anita and Jean-Claude could become Master's of all Tigers.
- Giacomo - Vampire, master of Magda.
- Fortune - A blue weretiger, Echo's animal to call.
- Echo - Fortune's master.
- Kaazim - A werejackal who helped Jake hide the golden tigers.
- Bilquees - Kaazim's master.
- Scaramouche - A wererat.
- Pierrette - A wereleopard.
- Pierrot - Pierrette's master.
- Hortensio - A wereanimal.
- Magnifico - Hortensio's master.