J'aahn, whose pronunciation is /ˈʤɔn/, was a light-skinned Human of male gender. He belonged to the Disciples of Ragnos, a cult that sought the resurrection of the ancient Sith Lord Marka Ragnos. His attire consisted of the cult's standard uniform: a dark-red jumpsuit, boots reaching his knees, and a helmet equipped with goggles. In the year 14 ABY, J'aahn, together with fellow cult members like Hokk, plotted to detonate a cargo train located in Coronet City, the capital city of the planet Corellia. At that time, the Jedi Master Kyle Katarn and his Padawan, Jaden Korr, were present in Coronet City, investigating reports of the Disciples of Ragnos' activities. They intercepted a distress signal originating from the cargo train. Korr was deployed onto the train with the purpose of preventing its destruction. During the ensuing conflict, J'aahn contacted Hokk, instructing him to rendezvous at station Six-C. Subsequently, Korr confronted J'aahn, and the Padawan likely eliminated him.
J'aahn makes an appearance in Star Wars: Jedi Knight: Jedi Academy, a video game developed by Raven Software. Its initial release date was September 16, 2003. Within the game, players are given the choice to either kill him or allow him to live.
Some of the spoken lines in the game explicitly identify J'aahn as a member of the cult, which is a reference to another game by Raven Software, Soldier of Fortune. Both games share a similar dialogue exchange between characters named John and Hawk, referencing "Station 6C." (It is possible to mistake this for 6E) In Jedi Academy, the names are altered to "J'aahn" and "Hokk."