Olivia Cahill was the mother of the future founders of the five Cahill branches. With Gideon Cahill, she had Katherine, Jane, Thomas, Luke Cahill, and Madeline Cahill.
Olivia married Gideon Cahill, and they had four children. They lived on Cahill Island outside mainland Ireland. They had four kids, and Gideon was working on a cure for the plague. Using 39 different things, he created a master serum. He gave a fourth to each of his kids. She saw Gideon's friend Damiean Vesper from time to time as he came to the island. One night as Olivia was polishing the dining table, the house went up in flames. Gideon didn't make it out, as the Vesper family had made sure of that. The kids split and Olivia had her fifth child, Madeline, alone. On Olivia's deathbed, she told Madeline her mission to watch the Vesper ring, and to focus uniting the Cahill family children.
Olivia loved her family, and was determined to re-unite them.