Dr. Lena Vargas is a biologist who works at the Detroit Zoo.
Lena previously had a relationship with Chuck, although they grew apart over time.
At some point, some smugglers blackmailed her, as they wanted to use her network of contacts to help sell endangered species on the black market. Due to Lena Vargas having brought many of the zoo's animals like Caesar through illegal procedures, she couldn't call the cops on the smugglers.
After Mari revealed her identity to her as Vixen, Mari had Lena schedule a meeting with the smugglers. With the help of Caesar, Mari ambushed the smugglers and got them arrested by the cops. Lena got immunity from her acts for having contributed in arresting such a global smuggling operation and used this fortunate turn of events to reconnect with Chuck.