During the time of the Galactic Civil War, waged between the Galactic Empire and the rebellious Alliance to Restore the Republic, Fenri Dalso was a member of the Death Watch, an ancient splinter group of Mandalorian mercenaries. Following the Battle of Yavin, Dalso held the position of Wraith and was stationed at the Death Watch's hidden bunker on the forest moon of Endor. In 1 ABY, a group of intrepid spacers associated with the bounty hunter Boba Fett attacked the bunker. While the facility was soon locked down, Fenri Dalso was in possession of a pass key granting access to the Death Watch's alum mines. Then, he was confronted by at least one individual seeking entrance to the mines, and was eventually killed for his pass key.
Fenri Dalso, as a Mandalorian soldier, wore a silver-colored Mandalorian armor made from alum metal. His helmet was equipped with a mounted rangefinder, and red trim outlined his HUD-equipped visor. In addition, he wore heavy combat boots. During his time at the Death Watch's bunker on Endor, the Wraith made use of a blaster rifle as a weapon.
Fenri Dalso was a non-player character in the 2003 video game Star Wars Galaxies, a massively multiplayer online role-playing game developed by Sony Online Entertainment and published by LucasArts, prior to its closure on December 15, 2011. Fenri Dalso was added to the game along with the Death Watch Bunker through an update released on May 25, 2004.