The 39 Clues Wiki
The 39 Clues Wiki
The information included in this article appears thoughout the entire 39 Clues universe.
This page is for the Cahill family as a whole. For Amy and Dan's family, see Cahill family (Grace).
Cahill Family
Cahill logo
Founder: Gideon Cahill

Olivia Cahill

Leader: N.A.
Strongholds: Cahill Command Center
Mascot: "C"
Skill: Depends on branch

The Cahill Family is the most powerful family in human history. Founded by Gideon Cahill and his wife, Olivia Cahill, around the 16th century, the family was split during a fire that destroyed Gideon's laboratory. This led to the creation of five branches - Lucian, Ekaterina, Tomas, Janus, and Madrigal. The family branches have fought for centuries, competing to find The 39 Clues first.


It is virtually impossible to find one significant figure in history born after the 1500s that's not a Cahill. As said above, the Cahill Family is split into five separate branches, the Ekaterinas, Tomas, Janus, Lucians and the Madrigals. Each branch has its own distinct qualities that separate the different branches. Some branches have a grudge against each other such as the Ekats and the Tomas. All of the branch's founders were one of the original Cahills; Luke Cahill founded the Lucian Branch, Katherine Cahill  the Ekaterina Branch, Thomas Cahill the Tomas Branch, Jane Cahill the Janus Branch, and Madeleine Cahill the Madrigal Branch. The reason you cannot find a significant figure that wasn't a Cahill after the 1500s is because back when only the original Cahills- Gideon, Olivia, Luke, Katherine, Thomas, and Jane- were alive, Gideon created a serum that cured the Black Plague. He drank the serum which made him stronger, younger, and more physical overall. His children wanted the serum (the whole thing), but he gave parts of the serum to each of his children, which made them try to kill each other for the whole thing. Katherine was interested in science and inventions, Jane into art and music, Thomas' had a lot of physical prowess and determination, and Luke was great at tactics and sneakiness. When the siblings got married and had children, their skills was passed down to their offspring. So Jane's children had an interest in the arts and musics, and excelled in them as well. These were passed down generation after generation. The hatred of each other, their parents interests/powers, and the longing for the completed serum never stopped.

Madeleine Cahill was never given part of the Serum, as she was born after her siblings parted their ways in hatred and Gideon died in the fire.

Ekaterina Branch

The Ekaterina (pronounced ee-CAT-er-ee-nah) or "Ekat" for short prize ingenuity, inventiveness, and curiosity.

39c crest ekaterina

Brilliant scientists and inventors are members of this branch. Their former leader was Bae Oh, who was arrested with the help of Alistair Oh(his nephew), for the murder of Alistair's father and the assault and battery of Alistair himself, and for many accounts of treachery. Alistair is the supposed new leader of the Ekats after the Book Series One, although this may be false. Katherine Cahill founded this branch. Their mascot is a yellow/orange dragon.

Janus Branch

39c crest janus

The Janus love the arts. Creative artists, art ranges from writing to painting to espionage to rapping to burglary to acting to singing, hail from this branch. Their current leader is Cora Wizard. Jonah Wizard is part of the Janus branch. Jane Cahill founded this branch. Their mascot is a green wolf.

Lucian Branch

The Lucians are leaders and spies. Due to the fact that some Lucians are ruthless and have an affinity for using poison, they are typically the most feared branch.

39c crest lucian

Their leaders were Vikram and Isabel Kabra. It is suspected that Ian and Natalie became the new leaders when Isabel was arrested and Vikram Kabra went into hiding. Irina Spasky is also a Lucian, but she died in a fire saving Amy, Dan and Alistair Oh in In Too Deep . Luke Cahill founded this branch. Their mascot is a red two-headed snake crossed through a sword although their crest has often changed.

Tomas Branch

The Tomas are athletes, explorers, and warriors. This branch, currently led by Ivan Kleister, who values endurance and strength above all. The Holts are the only Tomas in the books. It is notable that the Tomas were first on

39c crest tomas

the moon (Neil Armstrong) instead of the Ekaterinas. Thomas Cahill founded this branch. It's mascot is the polar bear.

Madrigal Branch

The Madrigals goal is to reunite the Cahill family. If a branch obtains too much power or too many clues, the Madrigals will destroy their work and if necessary, kill. The Madrigals are extremely secretive and highly skilled, due to madrigals needing to have been granted madrigal status, not just born into the branch. They tend to have members that are the heroes of history and some notorious people (William Shakespeare is one example, he disappeared for a few years). Grace Cahill was the Madrigal leader (revealed in book 7), but she left the branch to Fiske Cahill after Grace died. When the Madrigals want to tell people that the Cahill Family will be united again they use a C for their crest. If they want to frighten someone, they use the Madrigal M. More than half of Nobel Peace Prize winners are Madrigals. Madeleine Cahill founded this branch in order to get the Cahill Family together again. They are the only branch to not have been given part of the serum, but just have the ingredients that Olivia and Gideon have. The Madrigals have 2 crests, one for re-unification and one is for threatening the other branches.


The Official Crest

Family members