The God Calaan is incensed, humanity is facing its biggest struggle. The clerics believe that only those who are pure can live before Calaan. It is for this reason they reject the consumption of Elex and they will mistrust everyone acting contrary to this rule. To protect humanity from itself, they strive to gain more and more followers for their ideology.
Clerics have an advanced technology at their disposal. Besides laser and plasma weapons their arsenal, most notably, includes heavily armed fighting machines leaving only scorched earth once used.
Here you can have an insight into the various production steps from artwork to finished armor of the Outlaws in the game.