The first of the Gods of Zenn-La, it was Thrann who brought light to Zenn-La and was the keeper of the Zenn-Lavian belief system. Thrann is the one credited with leading Zenn-la down the path of pure science. He taught the Zenn-Lavians to believe only what they could see and to examine everything down to the last iota. His work turned Zenn-La into a virtual paradise, but had the ironic effect of causing the Zenn-Lavians to stop believing in him and his fellow gods.
Long did he and the other Gods live among the Zenn-Lavians until they all grew complacent. With their technological society, the Zenn-Lavians eventually no longer believed in their gods. The gods attempts to reconnect with miracles were ruined when the Zenn-Lavians analyzed each miracle in such detail and developed a rational explanation for it. It was when Galactus came to consume Zenn-La that they finally prayed for help, to which the Gods did not answer due to anger at being abandoned. .
Long had Thrann learned from the sacrifice of the Silver Surfer how to truly be a god and tried to rally the other gods against the threat of Mikaboshi. He had calculated the coming of the Chaos King long ago. When Mikaboshi attacked, Thrann attempted to sacrifice himself in the same way. Mikaboshi took all the Gods of Zenn-La into himself. Thrann became Mikaboshi's herald, and his advice to Mikaboshi provided doubt in his power.