During the Clone Wars, the influential planet of Thustra made moves to secede from the Galactic Republic. Republic forces, under the command of Jedi MasterYoda, attempted to sway the decision of the planet's king, Alaric, but to no avail. His subsequent death sent the planet of Thustra, and likely the entire sector as predicted by Supreme Chancellor Palpatine, into the hands of the Confederacy of Independent Systems.[6]
The Rebel Alliance Sourcebook indicates that Tierfon is in "Tierfon sector"; however, Heroes & Rogues, The Star Wars Sourcebook and Star Wars: Rebellion place places Tierfon in Sumitra sector. As such, "Tierfon sector" is here considered a colloquial name for Sumitra sector.
Sumitra sector was one of the many sectors included in Star Wars: Rebellion, which placed ten planets in the sector; however, Rebellion made numerous errors in its cartographic placement. As such, when its placements conflict with existing canon placements, they are overridden.[9] In the case of the Sumitra sector, that applies to Kashyyyk, Qat Chrystac, Woostri and Yavin. Kashyyyk is in the Mytaranor sector, Qat Chrystac is in the Parnabe sector, Woostri is in the Woostri sector, and Yavin is in the Gordian Reach[1]