Katherine Cahill was the founder of the Ekaterina branch of the Cahill family.
Katherine's parents were Gideon, and Olivia Cahill, born in 1492. She had a sister, and two brothers. One day, Gideon's house burnt, killing Katherine's father, leaving Olivia's status unknown. The four children argued, and tensions grew between them, Katherine even supposedly stealing something of Thomas's. He renounced her as his sister. Katherine scolded her family, saying Gideon valued secrets, Olivia loved him too much, Thomas ignored his duty, and that Jane was too young to survive alone, but she had nothing bad to say of Luke, just his stealth. Soon Katherine found the Ekaterina branch, and died at a unknown point in her life.
Like most present day members of the Ekaterina branch, Katherine was very smart, and had very good skills in the realm of science and inventing. She was the smartest of the Cahill children, and the Ekaterina branch still is the smartest.