Khe-Jeen was killed during the New Republic's campaign against Delak Krennel at the Battle of Distna.
Khe-Jeen Slee was introduced in Michael A. Stackpole's 1999 novel X-Wing: Isard's Revenge as Rogue Eight. The 1993 novel The Last Command features a Rogue Eight flying in the Battle of Qat Chrystac, set shortly before the events of Isard's Revenge, but it has never been confirmed that Slee was already with the Rogues at that point.
Khe-Jeen Slee was introduced in Michael A. Stackpole's 1999 novel X-Wing: Isard's Revenge as Rogue Eight. The 1993 novel The Last Command features a Rogue Eight flying in the Battle of Qat Chrystac, set shortly before the events of Isard's Revenge, but it has never been confirmed that Slee was already with the Rogues at that point.