Janns was a member of the Lost Tribe of Sith, a group of Human Sith who had settled on the planet Kesh during the Great Hyperspace War. He grew up the continent of Keshtah Minor during the Hilts Restoration and later participated in the Tribe's efforts to reach and conquer Alanciar, another continent in Kesh's southern hemisphere. Janns joined the Sith Sabers, a rank within the Tribe that was the equivalent of the Jedi Order's Jedi Knights. In 2975 BBY, Janns participated in the Tribe's expeditionary mission to Alanciar and served aboard the airship Candra. He was part of a ten-person crew that included Captain Edell Vrai, the uvak-tenderer Peppin, the thoughtcrier Taymor, four other warriors including his fellow Saber Ulbrick, and two Keshiri ambassadors including Tellpah. His captain Edell was also the commander of the Sith expedition and had invented the Tribe's airships after discovering that methane extracted from the volcano Sessal Spire could be used as hydrogen to power gasbags.
Janns and the Sith scouting fleet traveled across the Western Sea to Alanciar's southeastern peninsula region known as the Six Claws. Shortly after arriving in Alanciar, the Sith airships were attacked by black javelins fired from Alanciari ballista emplacements in the Six Claws and were pursued by the Alanciari air force, which consisted of armed uvak riders. Thus, the Sith had made contact with the Keshiri living on Alanciar but quickly learnt that they had a strong military that was capable of resisting invasion. In fact, the Keshiri geologist Adari Vaal, who had initially worked with the Tribe but later attempted to overthrow them, had fled to Alanciar over two thousand years ago. She succeeded in warning the Alanciari about the threat posed by the Lost Tribe. As a result, the Alanciari developed a highly militarized society based around resisting invasion by the Sith.
Janns was one of the six Sith crew who survived the Candra's crash-landing near Point Defiance, a signal station that was situated on the peninsular of Garrow's Neck. The other survivors included the mission's commander Edell, the uvak-tender Peppin, fellow Saber Ulbrick, and the Keshiri scholar Tellpah. Unseen, the Sith party had dropped north of Point Defiance while the balloon carried the wrecked gondola farther eastward. After traveling for a kilometer, the Sith party led by its commander Edell Vrai climbed a stony tumbledown which led to Point Defiance. His comrade Ulbrick was the first of the Sith party to climb up the summit. As a result, Ulbrick was hit in his right thigh by glass projectiles from a wooden ballista that had been fired by the Alanciari Wardmaster Quarra Thayn, who was protecting her wounded lover Jogan Halder, who had been crushed by the fallen uvak Starboard, who had been tethered to the Candra. Janns managed to dodge the projectile by diving for cover behind a ruined hut.
After a brief but fierce struggle against the Force-sensitive Alanciari woman, Janns and Peppin managed to overpower Quarra and take her and her companion Jogan prisoner. Quarra also revealed that she could speak the same language as the Sith and that the Alanciari had been well prepared for the Sith invasion. Meanwhile, the Keshiri scholar Tellpah attended to Ulbrick's wounds but the young Saber was unable to walk. To prevent the Alanciari from capturing a live Sith prisoner and to warn Quarra that she should cooperate with her captors, Captain Edell euthanized Ulbrick by beheading him. Janns and his Sith companions then entered Point Defiance where they attempted but failed to operate the station's semaphore machine, an Alanciari technology that was unknown to the Tribe.
However, Edell and Tellpah spotted an Alanciari ship in the horizon and decided to hijack and commandeer the vessel. After retrieving their Alanciari captives Quarra and Jogan from the latter's bedroom, the Sith party set out for the southern shore of the peninsula Point Defiance. There, they found a boat which they used to row to the Alanciari ship and seize it. This Alanciari ship turned out to be the fishing trawler Mischance and its crew fought to death against the Sith invaders, whom they had been taught from young to fear and hate. While the Sith managed to capture an Alanciari sailor, he resisted his Sith interrogators even until the point of death. Thus, the Sith gained no intelligence other than the fact that the Mischance had been hunting for crustaceans for the past week and was due to remain in the Southern Passage for a week before returning to port.
Later, Janns was presumably aboard the Mischance when the ship undertook its first transcontinental voyage from Alanciar back to the Tribe's home domain of Keshtah. During this voyage, the ship was captained by Edell's lieutenant Peppin and also carried the Alanciari prisoner Jogan Halder, who recovered from his injuries sustained on the night of the "first contact" and later became the Tribe's "ambassador" to the Alanciari. Halder subsequently convinced the Alanciari to submit to the Sith by claiming they were not a threat to them but were rather the Protectors, powerful gods in Keshiri religion. Meanwhile, Janns' commander Edell Vrai remained on Alanciar with his Alanciari guide Quarra Thayn. These two participated on a ground reconnaissance mission into the continent's interior and capital of Sus'mintri.
As a member of the Human Lost Tribe of Sith, Janns was Force-sensitive. He was also a warrior in the Sith Sabers, the Tribe's equivalent of the Jedi Knights, and was presumably skilled in lightsaber combat.
Janns first appeared as a minor non-point-of-view character in John Jackson Miller's novella Lost Tribe of the Sith: Pandemonium, which was first released on July 24 2012 as part of the mass paperback Star Wars: Lost Tribe of the Sith: The Collected Stories. This marks his only appearance in the Star Wars Expanded Universe.