Leviathan was Lucifer's brother and right-hand man. He was one of the mightiest Silver bloods. He was taken down by Gabrielle and imprisoned below Corcovado - the Gate of Vengeance due to the fact that he was too strong to be slain. Lawrence was the keeper of this gate and accidentally released Leviathan into the world by committing the greatest atrocity- killing of one's own kind. He rallied Lucifer's forces and searched for another gate to free his brother, stalking and kidnapping Schuyler Van Alen as a sacrifice to open it.