Sylvia was the junior member of a team from beyond the Milky Way Galaxy of two Ornithoid explorers in Human form who established an outpost, disguised as a large castle, on the planet Pyris VII. Landing parties from the USS Enterprise were trapped by Sylvia and her colleague Korob for observation in 2267. Information about Sylvia's species was displayed by the computer in Keiko O'Brien's schoolroom on Deep Space 9. (DS9: "A Man Alone", "The Nagus") Sylvia was played by actress Antoinette Bower.