In Book Seven: The Viper's Nest: Amy and Dan Cahill figure out they are Madrigals
i believe Amy and Dan are Madrigals.
In the book THE VIPER'S NEST it reveals the Dan and Amy are Madrigals.
Madrigals
madrigal
They are Madrigals. So are Grace and Hope Cahill.
Amy and dan are madrigals, the man in black is their great-uncle, fiske cahill, Nallie is a madrigal too, and Fiske and nellie are the new legal guardians of Amy and dan.
Amy and Dan are siblings. Amy loves Dan as a sibling and a brother.
Lucian, well that is Madrigal, a type of Lucian.
They are Madrigals descended from Madeline Cahill through Grace and Hope Cahill.
madrigals made by madeline cahill the last branch of the cahils
They are Madrigals. It comes from Grace and Hope's side of the family. Amy and Dan learn this in Viper's Nest, Book7.
The Madrigal leader was formerly Grace Cahill, but since shes has past, Amy and Dan are actually the branch leaders. I wonder if Amy and Dan know this.