The Vespers were an extremely dangerous organization and were enemies of the Cahills.
The Vespers were a family, dating back to the early 1500s, just like the Cahills. According to the Black Book of Buried Secrets, they evolved into an organization, and, according to George S. Patton, they recruit the best in the world and aren't picky apart from that the recruits need to have talent. Damien Vesper, the first Vesper, was Gideon Cahill's best friend until he betrayed him for the Master Serum, forcing Gideon to start the fire which burned down Gideon's laboratory, as seen on the back of the Thomas Jefferson Cards Card Combo. It is known that they are the Cahills' worst enemy. The Vespers have been sabotaging the Cahills from the start and framed Buchanan Holt for giving the Ekats the secret message. In the introduction to the The Black Book of Buried Secrets, Rick Riordan stated that every author agent (i.e. Margaret Peterson Haddix, Jude Watson, Patrick Carman, etc.) present during their meeting seemed to be terrified by the mere mention of the Vespers. They seem to be worse than any Cahill. As stated by William McIntyre, "They make Isabel Kabra look like Mother Teresa," and that from the reader's standpoint, Isabel is generally considered the worst, cruelest, and most ruthless Cahill. Isabel Kabra's parents had ties with the Vespers, as her maiden name was Vesper-Hollingsworth. Her mother’s last name was Vesper. Arthur Trent, Dan and Amy's father, was part of a family that had ties to the Vespers, but after marrying Hope, disowned himself from the family. Broderick Wizard, Jonah's father is most likely a Vesper, as Grace herself suspected him of being a Vesper. The Vespers attacked Amy, Dan and Fiske Cahill in Switzerland at a bank while the trio were dealing with Grace's account while retrieving Gideon's Ring. Amy and Dan were close to getting captured but were rescued by two skiers, Erasmus, and Fiske. In the Black Book of Buried Secrets, Amy calls Jonah Wizard, and, in a panicked voice (over much static), says, "They found us. The Vespers are coming." It is suspected that the Vespers are after Gideon's Ring. Many people think the Lucian branch and the Vespers are exactly alike, but there is a difference. The Vespers are full of ruthless people who would do anything to succeed and are not a family, while the Lucian branch are full of determined leaders and spies that are family.
One of the evidence of the existence of Vespers was at The Black Circle when Amy and Dan saw a picture of Winthrop Cahill seeing a man making a 'V' with his hands at the Lucian Stronghold. It is also possible that the Vespers control the FBI because when you search Vespers in the FBI database it deletes all your files(confirmed on Cahills vs. Vespers Mission 1).
Members of the Vespers
- Vesper One (The Leader) - Identity is a secret outside of the Council of Six. Leads and gives orders to all Vespers. Official identity: Damien Vesper III, aka Riley McGrath, Dave Speminer.
- Vesper Two (The Shield) - Oversees Vesper matters on behalf of Vesper One. Handles disciplinary matters. Official identity: Isabel Vesper-Hollingsworth Kabra . He/She seems to be based on Damien's servant, Balthazar.
- Vesper Three (The Mole) - Infiltrates targets inner circles. Official identity: Sinead Starling the mole.
- Vesper Four (The Scientist) - Creates surveillance and weapons tech, used by Vespers all over the world. Official identity: Sandy Bancroft.
- Vesper Five (The Spymaster) - Gains target's trust in order to destroy them. Official identity: Luna Amato. She seems to be based on Damien's spy, Maria.
- Vesper Six (The Enforcer) - Executing Vesper One's plans by any means possible. Official identity: Cheyenne Wyoming, Casper's twin sister. She seems to be based off of Damien's muscle, Craven.
Other Vesper Characters
- Ana Kosara - Pretended to be a Madrigal, but revealed in The Black Book of Buried Secrets to be a Vesper.
- Teodora Kosara - Vesper; revealed in The Black Book of Buried Secrets and on her official card.
- Casper Wyoming - tried to kill Amy, Dan, and Fiske in Switzerland in the book Vespers Rising.
- Bruno - a Swiss bank guard who was in league with Casper Wyoming in Vespers Rising.
- Mademoiselle Hubert - confirmed from Top Secret section of Card 334.
- Black Beard
- George S. Patton- A World War II general who invaded Casablanca in order to steal Gideon Cahill's ring.
- Johannes Kepler - Confirmed from the authors at Vespers Rising release signing and A King's Ransom.
- John Wilkes Booth - Assassinater of Abraham Lincoln. Revealed from the Morse Code on The Star Map Puzzle.
- Shep Trent - Cousin to Arthur Trent, most likely an inactive Vesper, if one.
- Adolf Hitler - A politician and leader of the Nazi Party. Führer of Germany during World War II.
- Jack Corelli - Questioned Amy and Dan right after the failed Vesper attack on Amy and Dan Cahill, and used to be a suspect for Vesper Six: The Enforcer.
- Katja Mavel - Attempted to hack into Mark Rosenbloom's E-mail account. Used to be a suspect for Vesper Five, the Spymaster. Still possible Vesper.
- George Bancroft - Shares Sandy Bancroft's last name.
- Sedlec Ossuary, Sedlec, Czech Republic
- Legnica, Poland
- Göreme, Turkey
- Mumbai Vesper Safe House, Mumbai, India
- Acropolis, Athens, Greece
- Kildare, Ireland
- Poenari Citadel, Romania
- Namorona River, Vatovavy-Fitovinany, Madagascar
- Boundary Ranges, Alaska, United States of America
- AWW Cartagena, Cartagena, Colombia
- Kraków, Poland
- Hashima Island, Nagasaki, Japan
- Casa Rosada, Buenos Aires, Argentina
- Great Pyramid of Giza, Giza, Egypt