Castiel is an [[Angel|Angel of Heaven]], who manifested on Earth inside his [[Vessel]], [[Jimmy Novak]].
Many angels laid siege to [[Hell]] to rescue [[Dean]], but it was Castiel who ultimately pulled Dean out. According to Castiel, he did so "because God commanded it". His hand print was burned into Dean's left shoulder
. It is later revealed that he was the one who raised [[Sam]]'s soulless body from [[Lucifer's Cage]].
After taking in the power of the millions of souls in [[ Purgatory]], Castiel declares himself the new [[ God]] - though [[ Death]] later calls him a " mutated Angel". After smiting many people he considered to be doing evil in God's name, he blacks out and loses control of his vessel, and his powers, to [[Leviathans]] possessing him. Conceding to [[Dean]] and [[Sam]]'s wishes, Castiel attempts to return all the souls and entities inside him to Purgatory. Some of the Leviathans hang on inside of his vessel ; they forcefully take control and state that Castiel is now dead.
Castiel has died twice and been resurrected: in [[5.01 Sympathy For The Devil]] after he was killed by [[Raphael]], and in [[5.22 Swan Song]] after he was killed by [[Lucifer]]. After he dies and comes back for a second time, Castiel states the he believes God brought him back "new and improved". He is able to heal others with a touch, as shown with Dean, and resurrect people at will, as shown with Bobby, and later implied in [[6.20 The Man Who Would Be King]]. He demonstrates [[telekinesis|pyrokinesis]] when he burns Crowley's bones.<ref name="six10">[[6.10 Caged Heat]]</ref> In [[6.19 Mommy Dearest]], Castiel shows the ability to incinerate lesser monsters, such as the [[vampire]] [[Lenore]], by touch. He also releases a blast of white light from his palms that instantly kills anything that sees it.
Castiel began a civil war in Heaven after the defeat of Lucifer to prevent Raphael from restarting the Apocalypse. After taking in the souls of [[Purgatory]], Castiel defeats Raphael. With the souls, he no longer is affected by an [[Angel Sword]]; he claims that he is no longer an angel, but the new "God". He sets about smiting his enemies and righting the wrongs he perceives, but he cannot keep the Purgatory creatures inside him at bay, and begins to deteriorate. He goes to Sam, Dean, and Bobby, who with help from [[Death]] rework the ritual to open Purgatory. The souls leave Castiel, and he collapses. He appears dead, but his vessel heals and he awakes. He apologizes to Dean, and pledges to find some way of redeeming himself. His plans are cut short when one (or some) of the creatures inside him ([[Leviathans]]) who managed to hold on takes over his body and declares that 'Cas' is dead.
See also [[Angel Garrison]], [[Angel Lore]], [[Castiel's Cell Phone]], [[Castiel's Trench Coat]], [[Castiel's Hair]].