"For thou hast said in thine heart, I will ascend into heaven, I will exalt my throne above the stars of God. I will sit also upon the mount of the congregation, in the sides of the north. I will ascend above the heights of the clouds; I will be like the most High.”
Lucifer, also known as the Light Bringer and the Light Bearer, was one of the first of God's creations, the second angel created after Michael, and His favorite. Lucifer was said to be the brightest in all of creation and was the most reverred to and the most praised among the angels for his beauty and power. This in the process, caused Lucifer to be prideful of himself. While he is highly regarded as an archangel, Lucifer is said to be a Seraphim and the first one to be created from the choir, thus he was appointed as the prince of the choir.
After creating Heaven and the Earth, Lucifer's pride grew. That is when God tasked him with watching over and guiding His creations. However, he became dissatisfied with following God alongside the fact that his Father favored the new creations known as humans, especially when having that a 'perfect' being like him would have to watch over these creatures like a shepard over his flock. He wanted to bring about a new era with himself on Heaven's throne. Lucifer rebelled against God, with the support of many angels. However, Lucifer was overcome by the archangel Michael, with God then banishing him and his followers from Heaven.
Lucifer fell for a long time, until he landed in Hell, and made it his domain. Since conquering Hell, he not only rules over the fallen angels, but also the demons that were native to Hell. He is known by many epithets, including Satan, the Devil, the "Prince of Darkness", Beelzebub, and Mephistopheles although these were later attributed to the actual demons themselves, the names themselves describe Lucifer's power and wickedness. After the birth of Jesus Christ, Lucifer offered him the world in exchange for his allegiance. However, Christ rejected him. Lucifer still yearns to return to Heaven and eventually take the throne he feels he is destined to sit on.
The reason for Lucifer's rebellion differs from interpretation to interpretation, however, three most accepted reasons fall in a refusal to bow down to mankind upon its creation, disagreement about God's plan of salvation, or the sin of Pride in aspiring to overthrow his creator and become ruler of Heaven himself. Nevertheless, he is widely and ultimately regarded as the angel that rebelled against his creator. For such an act, he was also identified with Satan himself even though the two are completely separate beings. But it is because of his rebellion and pride that his actions are considered so malevolent that he would be compared to the Devil.