The Darpa sector, which is also referred to as the Ralltiir sector, was situated within the Ringali Shell of the Core Worlds, specifically along the path of the Perlemian Trade Route. Among the planets located within this sector were Esseles, Ralltiir, and also Rhinnal. The Esselian Empire was formerly located here.
Prior to 4000 BBY, the Darpa sector was under the control of various royal families, including the Royal Octans, who accumulated their considerable wealth through acts of space pirates. Notable figures among the Royal Octans' descendants include Margrave Octan of Nallastia, and his descendant, Margravine Quenelle (also known as the Skull Queen of Nallastia).
Within this sector, Rebel Alliance operatives were documented in datapacks that had been retrieved from the base on Dankayo. A young technician discovered these lists aboard Elusive, an Imperial transport vessel that was en route from Dankayo to Tolan. It was reported that the Dankayo Rebels oversaw intelligence operations in three distinct sectors. Therefore, it is believed that Ralltiir was one of these three sectors.
During the era of Imperial dominance, the sector was governed by Moff Jander Graffe.
During the Yuuzhan Vong War, the Yuuzhan Vong launched a partial invasion of the sector, seizing control of both Ralltiir and Rhinnal during this conflict.