Zilssom was a male Tiburonian Starfleet officer in the 24th century. As of 2381, he held the rank of captain, and was commanding officer of the USS T'Pora, a Starfleet Corps of Engineers ship.

That year, in the wake of the Borg Invasion, Zilssom diverted the T'Pora from its surveying mission to assist the crew of the USS Enterprise in the establishment of a Denevan colony on the planet Ingraham B. (TNG novel: Losing the Peace)