Who's the actor?
Honestly, their behavior in general and their beliefs give them away as demon children…….
Isn't that what Pagans/Satanists/Luciferians do also?
As for true Christians, they confer with God by seeking His Doctrine in the inspired writings of the Prophets and the Apostles upon which the Congregation of Christ Jesus is being built. That Foundation is on what they are "based" and the only way they can know if it what they are deciding were of God.