Liz had a normal childhood until her pyrokinetic abilities began to manifest themselves when she was ten. Raised Catholic, Liz felt that the fires were a result of her sins, and for a short time managed to keep the fires under control by a combination of prayer and sheer force of will. However, in July 1973, at age eleven, she once again lost control. The resulting eruption destroyed an entire city block and, among the thirty-two fatalities, took the lives of her parents, brother, and pet dog. Liz's last uncontrolled manifestation took place on July 4, 1984.
After being juggled between extended family members following the death of her parents, Liz was taken in by the Bureau of Paranormal Research and Defense in May 1974, where she learned to control her power to some degree. In 1980, she became a full agent. She is often teamed with Hellboy and Abe Sapien. However, her childhood trauma has left her bitter and she often leaves the B.P.R.D. only to return soon afterwards.