Thull Vandron was a male hyperspace explorer and hero of the Galactic Republic circa 1000 BBY. Vandron led a fleet of starships against the Brotherhood of Darkness. He was also one of the architects of the Ruusan Reformations, in opposition of central power. However, when the Galactic Senate chose a different option, he retreated with a group of Core-Worlders and headed to a region in the southern part of the galaxy via secret trade routes. The region he chose was a cluster of worlds around a large nebula, which would later become the Senex-Juvex region. The nebula would later be named in his honor: Thull's Shroud.
Here Vandron was able to apply his system of noble houses in both the western and eastern parts of the nebula. The eastern systems were divided between the Houses of Vandron, Garonnin, Elegin, Anturi, Taneel, Petro, Araba, Hax, and Viholn and became the Senex. The western systems were divided between the Houses of Sreethyr, Carbinol, Hallikeenovich, Sisemon, Kassido, Kellermin, Pilor, and Mekuun.