Reo held the rank of Lieutenant Commander within the Galactic Federation of Free Alliances. He was stationed on the Victory I-class Star Destroyer named Admiral Ackbar as an engineering team member in 36 ABY, during the blockade that occurred at the Utegetu Nebula.
During the attack on the Galactic Alliance Fifth Fleet's ships by the Dark Nest, a clandestine Killik hive, Reo and Captain Urbok, the damage assessment supervisor on the Admiral Ackbar, met their death at the hands of Dark Nest assassins. The Killik venom rendered Lieutenant Aramb, a Gotal, paralyzed, which led to Yuul, a Captain who was given a battlefield promotion by Admiral Nek Bwua'tu, taking command of the ship's engineering division.
Reo's initial mention occurred in Troy Denning's 2005 novel, Dark Nest II: The Unseen Queen, which is a component of The Dark Nest Trilogy.