Thomas Chang was a male counselor in Starfleet in the 24th century. Chang's great-grandfather was a Romulan who had impregnated his great-grandmother when she was held in Romulan captivity. In 2376, and over seven years preceding, Chang was assigned to the USS Aldebaran. In April of that year the Aldebaran was assigned to defend Deep Space 9 whilst the station underwent a major refit. Chang and his crewmates died that month when the Aldebaran was destroyed by a trio of Jem'Hadar vessels attacking DS9. (DS9 novel: Avatar, Book One)