Toshiko Sato

Beautiful, brilliant, yet insecure, much of Tosh's private life remains a mystery, although it's known she has living family with whom she maintains a close relationship.

Despite her crush on Owen Harper, Tosh had a lesbian affair with a female alien who tried to use their relationship to gain access to her technology, previously confiscated by Torchwood. In order to gain Toshs' confidence the alien allowed her the use of a pendant which allowed the wearer to read the mind of anyone around her.

Heroically Tosh used the device to save the lives of a woman and her child, about to be murdered in a tragic domestic incident, but she became suspicious of the device when its use gave her insight as to how her team mates regarded her. She destroyed the pendant following the defeat of the murderous alien.