People who practice the Religion of Evil are those who:

• Harm other living beings.
• Eat too many animal corpses.
• Contaminate the environment.
• Lie and are hypocritical.
• Have sinful sex.

The followers of the Religion of Evil don't need to have any concrete beliefs, they can think they are atheists, agnostics, christians, muslims, buddhists, Hinduists...
Your beliefs don't define your religion, what defines your religion is your acts. True religion is not something to belief in, true religion is something you practice, the way you live.