I looked into your eyes from my seat on that plane. When you look into the eyes of God, you do not forget.
~ Thomas Coville to Kara.
Thomas Coville is a former lawyer who was down on his life, until his hope in it was restored by Supergirl when she saved the crashing plane he was on. After that, he went on to gather Kryptonian knowledge and create the Cult of Rao.
Thomas Coville was born and raised in National City. As an adult, he became a lawyer, leading a moderate life of success. However, Coville came to learn that his wife was cheating on him with her personal trainer. Afterwards, she divorced him. Coville subsequently went on a drinking binge that got him disbarred after some misdemeanor drunk and disorderly incidents.
In October 2015, Coville was on Flight 237, and noticed Supergirl standing on the wing. He was awed and amazed when he saw her fly away. Coville went on to find a a Kryptonian probe that had information on Krypton's worship of the Red Sun God Rao. Thomas form the Cult of Rao for which he recruited others who had been rescued by Supergirl. Coville also met a fallen Kryptonian priestess imprisoned at Fort Rozz, who told him all about the beliefs the people of Krypton]] had before Rao in his spiritual journey. He documented all his findings on Krypton's religion in a journal with help from Tanya, a member of the Cult of Rao.
The Cult of Rao was noticed by Supergirl's team in late 2017. They visit one of the meetings and confronted Coville, asking him to stop people from endangering themselves, but he recognized Kara as Supergirl, but promised not to divulge her secret, thinking that the encounter has been a test of faith from Rao himself.