Angel Luzbel (Lucifer) Is a being from the Mental Universe who rebelled against the preservation of the order inspired from an understanding of a Spiritual Universe whose existence couldn't be demonstrated.
Lucifer proposed to alter the way the evolutionary system was being organized. He wanted to allow a greater amount of free will to begin with the beings in the Mental Universe, and then to extend this to the evolving civilizations of the Physical Universe. In other words, he believed elieved that faith alone could not determine how life should be structured, and thus challenged the existing order.
Lucifer, who initiated a schism of cosmic proportions, disliked the idea of giving free will and psyquic potential to new humanities that did't even exist then because he felt that, perhaps one day, the new civilization would threaten or surpass the roles of those beings in the mental Universe.
He since tried to destroy our humanity using the help of his followers lead by Satanel.
(See the Rama Mission)