Alexia and Alfred Ashford first appear in Resident Evil Code: Veronica; British nobility who are descendants of Umbrella Corporation co-founder Edward Ashford, the 5th Earl of Ashford. Alongside Oswell E. Spencer and Dr. James Marcus, Edward Ashford was one of the main researchers working on the Progenitor Virus. Ostensibly the children of Dr. Alexander Ashford, the Ashford twins are revealed to be part of the eponymous Project CODE: Veronica.
In the late 1990s, the Umbrella research facility near Raccoon City infamously had major breakthroughs in research on the T-Virus, but the Ashford family had a major breakthrough on the virus before then. One of the Ashford twins, Alexia, created the t-Veronica Virus which, unlike the T-Virus, could potentially allow the infected to maintain lucidity and even control mutations. The genealogy and contributions of the Ashford twins, as detailed in Resident Evil Code: Veronica and Resident Evil: The Darkside Chronicles, are significant in terms of the Progenitor/T-Virus, and in terms of their role in one of the most well-received Resident Evil spin-offs.
Project CODE: Veronica
As British nobility, the Ashford twins are self-obsessed megalomaniacs, each doing what they deem necessary to maintain (or gain more) power. While both twins are intelligent, Alexia is the most intellectually impressive and scientifically minded twin. As such, Alexia receives blatant favoritism from their father, and Alfred grows up in awe of his sister. However, while still young, the twins discover they are not the children of Alexander Ashford, rather they are clones created from the embalmed remains of their ancestor Veronica Ashford, a part of Project CODE: Veronica.
Horrified by this information, the twins turn on their "father" and inject him with Alexia's newly created virus. Alexander mutates horribly, is considered a failed experiment by his children, and left imprisoned. He eventually gains the nickname Nosferatu, as seen in Resident Evil Code: Veronica. Alexia learns from this initial infection, called her virus the t-Veronica Virus, and injects herself an an effort to achieve world domination. She freezes herself cryogenically in order to slow the mutations caused by the virus and give her time to adapt. Alfred is tasked with releasing her when the time comes, and maintaining the Ashford estate in the interim.
The t-Veronica Virus
Alfred, unsure of his sister's survival, continues to work for Umbrella as his mental health deteriorates. While he is not as adept at virology, he becomes a cruel and unstable governer of Rockport Island and director of the Antarctic base where the t-Veronica Virus was created. Alfred becomes delusional and has a Hitchcockian personality split, in which he dresses and acts like his sister. In 1998, when the t-Veronica Virus accidentally becomes airborne after the H.F.C., an army employed by Umbrella's competitors attacks Rockport Island.
Resident Evil Code: Veronica and Resident Evil: The Darkside Chronicles differ in their accounts of how Alfred dies, but either way he dies shortly after freeing Alexia. In The Darkside Chronicles, Alexia kills Alfred for taking so long to rescue her, but in Code: Veronica, she awakens to find him dead from his injuries. Alexia is now in control of her mutations and sets her sights on becoming queen of the world. She has encounters with Claire Redfield, Albert Wesker, and Chris Redfield, who eventually defeats her.
While Alexia is ultimately defeated by Chris Redfield, she first mutates at will several times and becomes one of Resident Evil's multi-stage bosses. With the death of Alfred and Alexia, the Ashford family is brought to an end. The t-Veronica Virus is one of the most significant adaptations of the T-Virus in Resident Evil lore, and eventually is used with the G-Virus to create the C-Virus seen in the sixth game.