Belial is said to be a mighty and a powerful king over 50 legions, made after Lucifer. He appears as 2 beautiful angels sitting in a chariot of fire. His purpose (according to some branches of magic) is to make the mage popularly known, possibly getting them titles. It is also written that sacrifice must be given or he will lie to whoever summons him through sorcery.
In LaVeyan Satanism, however, Belial is seen as one of the Four Crown Princes of Hell (specifically, the North Crown), and states that his name means "'without a master'" and symbolizes true independence, self-sufficiency, and personal accomplishment. Belial represents the earth element, is the "Master of Mankind' and the "Champion of Humanity', and represents the carnal and base urges of humans.