For those who have not completed games in the Xenoblade Chronicles series, this page contains spoilers regarding the plot. Discretion is advised.
The forty-seventh successor to the throne of the High Entia, Emperor Lumian (English dub: /ˈluːmiən/), abolished the Order centuries prior to Xenoblade Chronicles because of their zealotry and the repercussions their prolonged existence could cause to the High Entia. The Order was relegated to the sidelines, and eventually not many knew that the Order still existed.
The Order is first seen by the party when a group of masked High Entia attack the party in Alcamoth. Alvis and Kallian come to investigate the attack, and Alvis suggests that they are members of the Order.
After a later attack on Melia by an assassin in the High Entia Tomb, it is discovered that the Order still operates, with Yumea as its leader. Yumea is then arrested for the attempted murder of Melia. The Order is not encountered at any point in Xenoblade Chronicles after this.
It is said that Tyrea was conceived by Yumea in a ceremony of the cult of unknown origin.
Most of the customs of the religion exposed in the game are from the memories of the old cult back when it was allowed within Alcamoth. Back then, anyone who did not follow the Order would be killed. In appearance, the cult refused the idea of the ethnic mixing of Homs and High Entia. They may or may not have been aware of the ultimate fate of the High Entia by Bionis. However, as implied by Yumea, they accept their transformation into Telethia as a part of being one with Bionis.