|“||I'm a CIA operative defending this country. After all the violence today, the infighting in our own government, the fact that our very own First Lady was plotting against her country....there's a chance here to use what they wanted for a greater good, to burn down the corruption that is eating away at this country and give us the fresh start we need.|
— Lydia Hall
Lydia is described as "Jessica Jones by night, Jessica Chastain in 'Zero Dark Thirty' by day" and a "highly accomplished actuary with a few twists up her sleeve". She is a former CIA case officer and co-instructor at The Farm. Originally posing as just another recruit, she and Owen Hall revealed her true role as a lesson to the others. As co-instructor, she's pushed Alex Parrish really hard during the training exercises. She was later charged for committing multiple felonies under the Espionage Act after leaking U.S classified intelligence to the internet.
Sometime in her life, Lydia joined the CIA, became an operative and served as a co-instructor at The Farm, along with Owen Hall, Angie Reynolds, and Jason Bowling. Secretly, Lydia ran an approved black ops program which eventually became the AIC. Dayana Mampasi, León Velez, and Ryan Booth were all recruited into this group.
A year later, she attended the G-20 summit in New York that was sabotaged by the Citizens Liberation Front. Towards the end of the hostage crisis event, she uploaded the intelligence drives containing classified information onto the internet. As a result of her action, she was incarcerated in a federal prison
- She is the daughter of FBI Deputy Director Owen Hall.
- She is a former CIA case officer.
- She is a former CIA instructor at The Farm.
- Her former cover work on CIA missions was in the role of an actuary.
- She is African-American.
- She speaks multiple languages.
- In AQUILINE, it was revealed that she escaped out of the crisis zone during the hostage exchange in between the events of Kubark and KMFORGET
- In the same episode, she encountered Alex after her escape and later decided to help her find the intelligence drives. Once, they found the drives, Lydia betrayed Alex, as her original plan was to destroy the drives. After she stole the drives from Alex, she quickly fled the area.
- In JMPALM, it was revealed that she recruited Ryan Booth, Dayana Mampasi and León Velez into a black ops division training program.
- In FALLENORACLE, it was assumed that she was disguised as an associate of the AIC due to covertly running the training program inside the CIA.
- In the same episode, Lydia admitted in a conversation with Ryan that the training program was fully approved and sanctioned by the CIA. Later, she provided a secret assignment to Ryan. She instructed Ryan to set a tap in the servers at the NSA building that will allow their covert group to monitor all emails and phone calls on the United States Eastern Seaboard. Soon after the tap was placed, Lydia mentioned that their success in the mission allowed the NSA to thwart a bombing attack at a Syrian refugee camp.
- Soon after, the black ops program turned into a rogue intelligence faction. It was formed by operatives who believed that certain sacrifices were necessary in order to eliminate government oversight of the black ops program. It is then assumed that she left the black ops program after the AIC formed.
- In EPICSHELTER, it was revealed that she set Alex up to believe that Dayana was a member of the AIC. Later, Dayana admitted that she was part of the special ops division of the CIA but her boss, Lydia, told her to find Will Olsen to destroy the drives. As the conversation occurred, Lydia shot Alex.
- In the same episode, Alex witnessed Lydia uploading the information from the intelligence drives to the internet towards the end of the 2018 Hostage Crisis. After being confronted by Alex, she explained that members of the AIC had planned to upload the contents of the drives into the internet. After stating that her allegiance was with the CIA and not the AIC, she elucidated to Alex that her real motive for uploading the intelligence data was to destroy the growing corruption within the United States government.
- Shortly after, Lydia got into a fight with Alex. Later, Alex won the fight. As a result of her actions during the hostage crisis, she is branded as a traitor to United States. After being charged of committing multiple felonies under the Espionage Act, due to leaking U.S classified intelligence to the internet, she is later incarcerated in an unnamed federal prison facility.
- In No Place Is Home, it was confirmed that she was killed by one of the assailants connected to Conor Devlin.