Ba'el was a half-Romulan, half-Klingon female born in a Romulan prison camp on Carraya IV. Her father was Tokath, a Romulan involved in the Khitomer Massacre of 2346, and her mother a Klingon survivor of that attack named Gi'ral.
In 2369, Worf visited the planet, investigating rumors that his father Mogh was among the captives. Ba'el fell in love with him, and defended him when Tokath threatened his life. When Worf left, taking a number of young Klingon prisoners back to the Klingon Empire, Ba'el decided to stay, believing that because of her mixed heritage, she would not find acceptance outside the camp. (TNG episodes: "Birthright, Part I", "Birthright, Part II")
In 2376, the camp in Carraya IV was attacked by Gorrik, son of Gannik, leaving Ba'el one of only three survivors. She was found and rescued by former camp resident Toq, who brought her back to Qo'noS and helped her reunite with Worf, then Federation Ambassador to the Klingon Empire. Worf helped her secure a job at the Federation Embassy on Qo'noS as an assistant to events coordinator Eduardo Mazzerone. (KE novel: A Burning House)