A fallen angel is a celestial being, once good, who rebelled against God and was cast out of heaven, becoming associated with evil, demons, and temptation, with Lucifer (Satan) as the most prominent example. They chose to defy God, often out of pride, led by Lucifer, who refused to bow to Adam. Satan (Lucifer) is the leader, with other fallen angels serving as princes of Hell, or as entities such as Belial and Samael. Fallen angels are commonly identified as demons, spirits of evil, and sources of temptation and spiritual warfare. They are depicted as spirits or entities that bring corruption, often possessing or influencing humans, and are central figures in Abrahamic faiths (Christianity, Judaism, Islam). However, specific beliefs about them vary by religion. They can appear in physical form, interact with humans, and even procreate with women (as in Genesis), resulting in giants (Nephilim).