- "Addictive, is it not? The Lignan, I mean."
- ―Saes Rrogon
Lignan was a rare ore that was extremely powerful in the dark side of the Force. One of the only places it could be found was in the Phaegon system, on the moon of Phaegon III. If drawn upon while the user was utilizing the Force, the ore was able to greatly augment the user's abilities, although the ore itself burned to ash as it was used up. It was noted to give a light-headed feeling after its use. In 5,000 BBY, Sith Lord Naga Sadow sent Captain Saes Rrogon with the Harbinger and Yaru Korsin with the Omen to mine Lignan ore for use during the impending invasion of the galaxy by the Sith Empire. However, their mission was foiled when Jedi Master Relin Druur and Druur's Padawan, Drev Hassin, assaulted the Sith. As the Sith attempted to escape, the Omen was knocked off-course to the remote planet Kesh, where the Sith survivors remained stranded until 41 ABY, while the Harbinger jumped through an unstable hyperlane, causing it to travel through time to 41 ABY. The Omen survivors used the Lignan to make Lignan crystals to use as lightsaber crystals for the highest ranking members of their Tribe.
- Lost Tribe of the Sith: Precipice (First appearance)
- Lost Tribe of the Sith: Skyborn (Mentioned only)
- Lost Tribe of the Sith: Paragon (Mentioned only)
- Lost Tribe of the Sith: Savior (Mentioned only)
- Riptide (Indirect mention only)
- Vortex (Mentioned only)