Lisa Addison

Lisa Addison was a computer programmer, the sister of Matt Addison, and, through some subterfuge, an employee of the Umbrella Corporation.

Early life
In college, Lisa was a student of a man named Dr. Simon Barr, regarded as the top man in applied AI. At the beginning of the course, Barr promised his students that none of them would get higher than a B, and most would get C's or D's. Lisa was determined to prove him wrong, and after months of agonizing work, she received an A, though Barr told her that she would become nothing better than a corporate drone who was simply better at it than most. Barr, for his part, would go on to be involved with the development of the Red Queen.

Lisa was at one point married, but divorced her husband after the death of his mother. Lisa was good friends with Mahmoud al-Rashan, whom she met working for Citibank, and his wife Fadwa. When Mahmoud died after complications following surgical work on an ulcer, it was discovered that drugs manufactured by Umbrella had only worsened his condition. It was then that Lisa developed a deep, abiding hatred for Umbrella.

Infiltration
In 2002, with support from her brother, Lisa sought and gained employment with Umbrella, assigned to the computer security division working out of The Hive. The purpose of this being to recover incriminating evidence of Umbrella's crimes, a task she was well suited to. She was forced to work closely with Dr. Barr's creation, the Red Queen, and found that duty quite unpleasant.

While in the Hive, Lisa created a security protocol requiring all employees to change their password for the computer network every eight days. She knew that most people would forget, which was another part of her plan. When someone forgot to change their password, they were locked out of the system until Lisa could help them. After resetting their password, Lisa would get a momentary glance at whatever information the person in question was trying to access, in the few seconds it took the Red Queen to realize that she didn't have clearance to see the data. It was this method by which Lisa hoped to secure the evidence against Umbrella. It was also by this method that she came to conspire with Alice.

Conspiracy
When Alice, the Hive's security chief, requested help with the password system, Lisa readily complied, eager to see what data the head of security would access. What Lisa didn't know was that Alice had set the whole thing up to determine Lisa's plan.

After a lunch in Raccoon City, Alice showed Lisa security footage of Lisa peering intently at her monitor during the password trouble-shooting session, admitting that she had realized what the other woman was up to. This was the preface for a more shocking revelation: Alice was also planning to move against Umbrella, and wanted Lisa's help to do it. She promised to help obtain data on the new biological weapon, the Tyrant virus, in exchange for Lisa's promise to bring Umbrella down, a plan which Lisa readily agreed to.

Death
Unbeknown to either of them, Alice's partner, Spence Parks, had eavesdropped on their conversation, and was planning himself to steal the virus. He released the virus into the Hive's air conditioning system and made his escape. The Red Queen, in an attempt to stop a disastrous viral outbreak, sealed Lisa's office and filled it with halon gas, suffocating everyone within.

Hours later, as Umbrella's commando team came into the Hive to investigate the incident, Lisa's own brother, Matt went in with them to find her, or some of her gathered evidence. He was met by Lisa's corpse, reanimated by the T-Virus, who attacked him. Lisa was killed for the final time by Alice, who bashed her skull in with her own paperweight.