During one particular Enclave meeting, Lilian expressed her concerns for the Magister's automatons and the possibility that an army the Shadowhunters could not defeat was being made. The others dismissed this as mere speculation. Months after, Lilian had seemingly been threatened by Benedict Lightwood into supporting his claim that Charlotte Branwell was unfit to run the London Institute, thus allowing him to challenge Charlotte for the position. When she commented about how the search for Axel Mortmain was being turned into a power game, Consul Josiah Wayland asked her if she was withdrawing her support for Benedict. A look from Benedict stopped her from speaking further.
She also attended the emergency meeting Consul Wayland called to discuss Charlotte's position as head of the London Enclave. She was among those who survived the onslaught of Mortmain's automatons in the Council Hall.
Twenty-five years later, Lilian was still an active member of the London Enclave. She attended a meeting held by Charles Fairchild to discuss the recent and strange demon attacks. When it was announced that the city was under quarantine and Portal travel had been suspended, Lilian spoke up expressing her distrust of them anyway; followed by a strange story of parabatais ending up with each other's limbs, which most of the others ignored. She later raised the concern that though they were under quarantine, it didn't mean the demons wouldn't leave the city. Will Herondale attempted to ease her concern by stating that other nearby Institutes would be patrolling outside the city to make sure if they did leave, they were caught.
A few weeks later, she became a victim of the serial killings in London. While coming out of her house in the morning, she was attacked by Belial in Jesse Blackthorn's body—whom she recognized as his late father. Belial stabbed her several times with an adamas blade. Belial then used a pithos to steal her Precision rune. Her screams were heard by Thomas Lightwood and Alastair Carstairs, who rushed to her aid, and in his hurry Belial dropped the pithos and Lilian grabbed it. Barely alive and shocked to have seen someone she believed dead, she attempted to tell Thomas who the killer was but died before she could explain further and say his name.
Lilian had dark, catlike eyes, dark hair, and, according to Tessa, a secretive demeanor.