The Sixth Line was a militant faction of the Jedi Order that was active during the Galactic War between the Galactic Republic and the Sith Empire. They took their name from the "sixth line" that they added to the Jedi Code: "There is no contemplation, there is only duty." Led by the Jedi Master Surro and several other Masters, the Sixth Line worked as a strike unit for the Republic, primarily on the orders of the Republic Strategic Information Service. The Sixth Line was deployed on the planet Balmorra in the aftermath of Grand Marshal Cheketta's failed defense of the Balmorran Arms Factory.
Later in the war, when Agent Theron Shan discovered that the former Sith Emperor Vitiate was active on the planet Ziost, he called the Sixth Line to Ziost, but Vitiate possessed the entire Sixth Line along with the planet's population. The vast majority of the Sixth Line perished in the cataclysmic Invasion of Ziost.
Years after, during the final confrontation with Tenebrae, members of the Sixth Line were among the spirits witnessing his final death.