Ethos Headquarters, also known as Ethos HQ, is a lavish church-like building on one of the islands in the Aquvy Archipelago in the southern portion of the Xenogears world. The Ethos Society operates out of this golden building. The first unauthorized people to see this facility and uncover its secrets were former Etone Billy Lee Black and his companions led by Fei Fong Wong. The secrets and lies uncovered beneath the Ethos HQ destroyed Billy's already shaken faith in everything he thought he knew and also helped to seal the fate of the false church.