The Harbinger was a Sith dreadnaught active in 5000 BBY, during the Great Hyperspace War. It was commanded by Saes Rrogon, a Jedi-turned-Sith Lord. The Harbinger and another dreadnaught, the Omen, were transporting Lignan ore to Sith Lord Naga Sadow when the two ships were ambushed by a Jedi starfighter. Harbinger was infiltrated by Relin Druur, Saes' former Jedi Master, who managed to sabotage its hyperdrive while Druur's Padawan, Drev Hassin, held off several of Harbinger's own fighters. Eventually, Hassin managed to ram the Infiltrator into the Harbinger's bridge, causing the Harbinger to crash into the Omen just as the vessels escaped into hyperspace. The collision knocked the Omen off-course, causing it to crash into the remote planet of Kesh.
Harbinger itself jumped through an unstable hyperspace tunnel which caused it to travel through time to the year 41.5 ABY. There, Relin again faced Saes and used the Lignan ore power to kill Rrogon. Then, Druur sent the Harbinger crashing on the surface of the frozen moon below, destroying the ship and killing Druur.
- Lost Tribe of the Sith: Precipice (First appearance)
- Lost Tribe of the Sith: Savior (Mentioned only)
- Lost Tribe of the Sith: Pantheon (Mentioned only)
- Riptide (Mentioned only)