Seruba Velak was the wife of Rivesh Mantilax.
Seruba was an ambassador from her home planet, but she was ambushed on a peace mission, landing in Roswell, New Mexico in 1947. This resulted in her home planet being invaded by the Viperox. She was found by the US Military and taken to Area 51, where she was kept in a lab. When the Tenth Doctor, Cassie Rice and Jimmy Stalkingwolf were taken to Area 51 in 1958, they escaped and found her. The Doctor tried to release Seruba but soldiers forced the three to flee. She was later reunited with Rivesh Mantilax, but separated from him by a panel of glass.
After Lord Azlok killed Rivesh, the Doctor freed Seruba. She noted Rivesh was not fully dead, so she and the Doctor looked for a cure to revive him. She was attacked by the Skorpius flies but with the Doctor's help, she got away by hiding in a crate. Seruba reunited with her husband and revived him. The Doctor convinced Rivesh not to wipe out the Viperox. The Doctor tweaked their weapon so it would drive the Viperox away from Earth.