Martha Vickers

Martha was a member of the cult of the Cailleach under Leonard de Vries in 1978.

Biography
Martha was a local schoolteacher who had joined the cult due to her friendship with de Vries, and because the cult brought colour into her dull life. (PROSE: Doctor Who and the Stones of Blood)

Martha was unwilling to sacrifice the Fourth Doctor to the goddess, and after he escaped, an Ogri killed her and de Vries. (TV: The Stones of Blood)