Madeline Cahill was the last daughter of Olivia Cahill and Gideon Cahill, the founder of the Madrigal's
Madeline was Olivia's last child, and was born after Gideon had died and the family split. Olivia was always distraught at the fact that her children all hate each other. On Olivia's deathbed, she told Madeline that she should try to reunite the other branch founders and save the family from the true threat, the Vespers. Madeline accepted, and was also tasked with holding on to the ring of Damian Vesper, the man responsible for Gideon's death. Madeline founded the Madrigal branch, and continues to strive for those goals today.
Like the Madrigal's of today, Madeline was dark, shady, and mysterious, having certain great talents, but shy, preferring to stay in the shadows.