Jarmus Lenn was a Bajoran woman. For many years, she was a member of the Bajoran Militia and one of Odo's deputies. After Bajor joined the United Federation of Planets, Jarmus joined Starfleet. She retained her duties as a security officer aboard the space station.

In January 2377, Jarmus was part of the team that searched for Taran'atar after he attacked Kira Nerys and Ro Laren before disappearing from sight. Jarmus viewed the activity log of the turbolift the Jem'Hadar had used, discovering it had been to the fusion core and runabout Pad A. (DS9 novel: Warpath)