|The following is based on information from Fallout: Brotherhood of Steel.|
The Texas Expedition was an expeditionary force sent to the former state under orders from High Elder Rhombus and is the playable faction in Fallout: Brotherhood of Steel and the canceled Fallout: Brotherhood of Steel 2.
After the death of John Maxson, Rhombus, the head of the Brotherhood's Paladins, became the new High Elder. After the death of the Master, the Brotherhood of Steel helped the other human outposts of the former American Southwest drive the mutant armies away with minimal loss of life on both sides of the conflict. However, a super mutant faction under the leadership of Attis moved east and attempted to recreate the mutant army in Texas using the Secret Vault. Rhombus, despite some criticism from the ruling council of the West Coast Brotherhood of Steel, started a crusade against the still existent threat of the super mutant army, now led by Attis.
They traveled eastward to Texas, arriving by 2208. There, he discovered a prototype vault which was abandoned and installed the Brotherhood's main base of operation in this area. Their principal mission was to eradicate the menace of all super mutants. For this reason, they created a new Texas Brotherhood icon, which featured a pair of wings, topped by dual pistols, all of a red color. The Texan Brotherhood was also open to recruiting outsiders, including ghouls.