Youngarch was the title bestowed upon the protégé of the Eldarch, leader of the Order of the Blue Light of the Sa'ari people of T'lessia. Selected from amongst the lighters of the Order, upon acceptance the Youngarch would gradually be taught everything that the Eldarch knew of "the Blue" and how to manipulate it. As part of her role, she was also ordained to eventually succeed her mentor upon the elder's death. Most Eldarchs chose their Youngarchs based on a number of factors, including strength, mental aptitude, and intuition; often, the elder would have had opportunity to serve alongside the potential candidate. Youngarchs typically remained within Order monasteries, where they spent much of their time studying and practicing.
As of 44 ABY, the title of Youngarch was held by Pelenora T'Yelc, who had been appointed to the role by Bellinega T'Ledra. Unlike many of her predecessors, however, T'Yelc had chosen to serve as an officer with the Tal'adin Constabulary; though formal introductions with the so-called "Starborne Ones" Laera Reyolé and Silas Dan'kre had been made by Bellinega, it was she who had initially made first contact after their crash-landing on T'lessia. At the final resolution of the Sa'ari Civil War, the title of Youngarch passed on to Fua T'Ooro.