Devor was a member of a group of mercenaries that boarded the USS Enterprise-D during preparations for a baryon sweep in 2369 at Arkaria Base with the intent of stealing trilithium resin.
Their plan was foiled when they were noticed by Captain Jean-Luc Picard, who was still aboard the ship, but assumed they were base personnel. Devor was the first of the mercenaries to be encountered by Picard, who only realized their plan after being attacked without provocation, and subdued him with a Vulcan nerve pinch. When he came to, Picard questioned him about what was going on, and when Devor refused to answer, Picard used a hypospray on him. Devor was presumably later killed by the baryon sweep. (TNG: "Starship Mine")
Devor was the first of several roles played by Star Trek: Voyager regular Tim Russ.
In the first draft script his name is spelled "Davor" and he is described as an alien.