At the end of Machine, after Frank Collins claims to have seen a warthog on the beach of Outpost High Ground, Kelen criticizes Jack O'Brien for supposedly changing his armor to a captain's uniform in the absence of Cayde Jasper, but O'Brien dismisses Collins and Diego Jones agree with him and insisting he had always been captain. Kelen simply exclaims that she hates her coworkers.
Immediately after driving out of Outpost High Ground in her mongoose, in the opening flashback of Ambush, Kelen and O'Brien are shot in the head by a plasma blast. Later, in Deception, Spartan Louie Vargas and five repurposed protocol robots investigate the attack and discover Kelen and O'Brien's dead bodies before Louie is shot and killed in a similar manner.
She does not speak in WarGames, despite being planned to for the cold open of Ambush, due to her line being cut for time. To make up for her lack of dialogue, Syp The Mighty made sure to include Kelen's rocket launcher, which she gained in the finale of Major Malfunction.
Her first name is never stated in-series, with Syp coming up with it after the release of WarGames. During the production of Major Malfunction, its creators considered her first name to be Ember.
