Chief Petty Officer Dennisar was a 24th century Orion man who served Starfleet as an enlisted security team member aboard the Federation starship USS Titan by the year 2381. During the invasion of the Borg Collective early in that year, Dennisar took part in several battle drills run by Ranul Keru, along with fellow security officer Gian Sortollo. Dennisar was "killed" in a simulation when a Borg ship become an active participant to repel boarders and pulled him into the bulkhead.