Detailed history is here on his wiki page! And for some reason I wrote my own condensed version, so here's that too.
Castiel is a very, very old being. He was present at the beginning of time when his Father created the humans, and watched as they carried out now historical events. In more recent times, Castiel (along with a group of other angels) had laid siege to Hell in order to rescue the soul of one Dean Winchester, known to them as the Righteous Man. Castiel was the one who found Dean's soul and raised him from perdition, but not before the first of 66 seals that held Lucifer's cage together was broken. Not that they let the Winchesters in on this until much later.
In any case, with Dean back on Earth and the whole Apocalypse thing triggered, the angels were dispatched to Earth for the first time in over two thousand years. As angels are "wavelengths of celestial intent", taking on a human vessel was the only way to do this. Castiel's vessel is a religious family man named Jimmy Novak (who at this point is possibly dead, though Castiel continues to hold onto the man's appearance while on Earth so who knows).
Castiel (and subsequently the whole angel species) is officially introduced in season four. Up until the very end of this season, Castiel remains a soldier who is loyal only to Heaven and his Father (though is intrigued by humanity). He followed orders without wondering why, just as he always had... but as the season progressed Castiel started to become more and more aware of these odd human feelings that had never really bothered him before. Uncertainty. Guilt. Looking at the choices the fallen angel Anna had made, listening to her tell him he needed to think for himself and listening to Dean tell him all sorts of blasphemous things like free will slowly began to change him.
At one point, Castiel was going to tell the Winchesters the truth. About the Apocalypse, his orders, everything. He was going to help them -- but before he could, he was sent back to Heaven for a short time.
When he returned, he had "learned his lesson" and angrily told Dean that he served Heaven, not man.
But not so far down the road when Dean asked him again to help him, Castiel gave in and stood up for himself and his new way of thinking. By doing so, he rebelled against all of Heaven, chose the humans over his own family, all because he was sure that it was the right thing. He managed to send Dean to his brother so the boys could stop the breaking of the final seal, but they failed and Lucifer was released onto the Earth. Trying to protect the Winchesters, Castiel was killed by the Archangel Raphael.
However, it turns out in the fifth season that Castiel has been revived by an unknown force that he believes to be God. He holds onto his Grace (basically his angelness) but because of his rebellion he is cut off from the power of Heaven and is unable to access some of his powers, such as smiting demons and healing. That said, Castiel remains a powerful ally and with his new freedom is able to spend more time with the Winchesters. As they try to find a way to send Lucifer back to Hell and fight everything in between, Castiel acts as their guardian angel and goes to them whenever he is called. For a time, Castiel also spends his time searching for his Father, still believing in Him, but eventually his faith is shattered when the boys go to Heaven and discover that God is not only MIA, but he doesn't really give a shit about his children anymore either.
Some time after giving up on God and shifting his faith entirely to the Winchesters, they find a way to seal Lucifer in his cage again. During their final altercation with the devil, Castiel is once again killed by an Archangel (Lucifer this time) for helping the Winchesters.
And once again he is mysteriously brought back! He believes it to be the work of God yet again. Castiel is even more powerful than before, and as Heaven explodes into anarchy over the failed end of times prophecy and sudden, distinct lack of a chain of command, many of the other angels believe Castiel to be chosen and lay their loyalties with him. So with Sam stuck in the cage with Lucifer, Michael and his little brother Adam, Dean is left on his own. He goes to an old girlfriend and her son where he builds a new, normal life, and Castiel returns to Heaven to restore order.
Of course that doesn't quite turn out so well. He's no match for Raphael, who is stronger than him in every regard.
But Castiel is no longer bound by the laws Heaven placed on him. He has free will, and tons of angels looking to him as their leader, not Raphael. For a while the angel feels stuck and almost goes to Dean in order to ask for his help... but finds himself unable to bring himself to do it. Dean is finally happy and free from the life of hunter, and Castiel knows he can't take that away from his friend. He is soon approached by a demon named Crowley (who also now happens to be the new King of Hell in Lucifer's absence) and offered a plan, and a deal:
Find Purgatory (the place monsters go when they die) and split the 30 - 40 odd million souls in there 50/50. With the immense power that would come from so many souls, Castiel would be powerful enough to take out Raphael and thereby avert another Apocalypse. To show Castiel just how serious he was, Crowley offered 50 thousand souls from the Pit upfront to give him the boost he needed to deliver the first strike against Raphael.
Castiel accepted.
He then returned to Heaven and threw in the gauntlet. He let it be known that from now, you either stand with Raphael or you stand with him.
"And so went the long road of good intentions."
Powers/Skills:
Even low ranking angels in Supernatural are insanely powerful, so Castiel like his angel buddies already here will also have to be powered down. The basic bits are as follows:
• Teleportation: So long as an area is not guarded by angel warding sigils, Castiel can instantly teleport anywhere.
• Angelic Endurance/Strength: He is able to take quite a few hard hits without dying (as in, stabbings and shotgun shells to the chest don't really slow him down) and also possesses strength beyond that of the strongest human. Castiel can do things like throw people around no problem, push around furniture with a simple push of one hand, and survive falling out of a fourth story window and crushing the car he lands on without more than a scratch.
• Supernatural Perception: Such as being able to see ghosts and reapers, seeing the true face of demons and angels, and being able to tell if someone is some form of supernatural creature or human.
• Some Touch Based Skills such as Induced Sedation where simply a touch to the forehead can cause a person to temporarily lose consciousness and Healing of even the worst injuries. (Though for the purpose of the roleplay, these can be totally watered down to just being able to heal some cuts or make a person dizzy or something if necessary.)
He is also proficient in hand to hand combat and knife fighting, so even without his powers he should be able to hold his own in a fight.
Castiel | Supernatural
Detailed history is here on his wiki page! And for some reason I wrote my own condensed version, so here's that too.
Castiel is a very, very old being. He was present at the beginning of time when his Father created the humans, and watched as they carried out now historical events. In more recent times, Castiel (along with a group of other angels) had laid siege to Hell in order to rescue the soul of one Dean Winchester, known to them as the Righteous Man. Castiel was the one who found Dean's soul and raised him from perdition, but not before the first of 66 seals that held Lucifer's cage together was broken. Not that they let the Winchesters in on this until much later.
In any case, with Dean back on Earth and the whole Apocalypse thing triggered, the angels were dispatched to Earth for the first time in over two thousand years. As angels are "wavelengths of celestial intent", taking on a human vessel was the only way to do this. Castiel's vessel is a religious family man named Jimmy Novak (who at this point is possibly dead, though Castiel continues to hold onto the man's appearance while on Earth so who knows).
Castiel (and subsequently the whole angel species) is officially introduced in season four. Up until the very end of this season, Castiel remains a soldier who is loyal only to Heaven and his Father (though is intrigued by humanity). He followed orders without wondering why, just as he always had... but as the season progressed Castiel started to become more and more aware of these odd human feelings that had never really bothered him before. Uncertainty. Guilt. Looking at the choices the fallen angel Anna had made, listening to her tell him he needed to think for himself and listening to Dean tell him all sorts of blasphemous things like free will slowly began to change him.
At one point, Castiel was going to tell the Winchesters the truth. About the Apocalypse, his orders, everything. He was going to help them -- but before he could, he was sent back to Heaven for a short time.
When he returned, he had "learned his lesson" and angrily told Dean that he served Heaven, not man.
But not so far down the road when Dean asked him again to help him, Castiel gave in and stood up for himself and his new way of thinking. By doing so, he rebelled against all of Heaven, chose the humans over his own family, all because he was sure that it was the right thing. He managed to send Dean to his brother so the boys could stop the breaking of the final seal, but they failed and Lucifer was released onto the Earth. Trying to protect the Winchesters, Castiel was killed by the Archangel Raphael.
However, it turns out in the fifth season that Castiel has been revived by an unknown force that he believes to be God. He holds onto his Grace (basically his angelness) but because of his rebellion he is cut off from the power of Heaven and is unable to access some of his powers, such as smiting demons and healing. That said, Castiel remains a powerful ally and with his new freedom is able to spend more time with the Winchesters. As they try to find a way to send Lucifer back to Hell and fight everything in between, Castiel acts as their guardian angel and goes to them whenever he is called. For a time, Castiel also spends his time searching for his Father, still believing in Him, but eventually his faith is shattered when the boys go to Heaven and discover that God is not only MIA, but he doesn't really give a shit about his children anymore either.
Some time after giving up on God and shifting his faith entirely to the Winchesters, they find a way to seal Lucifer in his cage again. During their final altercation with the devil, Castiel is once again killed by an Archangel (Lucifer this time) for helping the Winchesters.
And once again he is mysteriously brought back! He believes it to be the work of God yet again. Castiel is even more powerful than before, and as Heaven explodes into anarchy over the failed end of times prophecy and sudden, distinct lack of a chain of command, many of the other angels believe Castiel to be chosen and lay their loyalties with him. So with Sam stuck in the cage with Lucifer, Michael and his little brother Adam, Dean is left on his own. He goes to an old girlfriend and her son where he builds a new, normal life, and Castiel returns to Heaven to restore order.
Of course that doesn't quite turn out so well. He's no match for Raphael, who is stronger than him in every regard.
But Castiel is no longer bound by the laws Heaven placed on him. He has free will, and tons of angels looking to him as their leader, not Raphael. For a while the angel feels stuck and almost goes to Dean in order to ask for his help... but finds himself unable to bring himself to do it. Dean is finally happy and free from the life of hunter, and Castiel knows he can't take that away from his friend. He is soon approached by a demon named Crowley (who also now happens to be the new King of Hell in Lucifer's absence) and offered a plan, and a deal:
Find Purgatory (the place monsters go when they die) and split the 30 - 40 odd million souls in there 50/50. With the immense power that would come from so many souls, Castiel would be powerful enough to take out Raphael and thereby avert another Apocalypse. To show Castiel just how serious he was, Crowley offered 50 thousand souls from the Pit upfront to give him the boost he needed to deliver the first strike against Raphael.
Castiel accepted.
He then returned to Heaven and threw in the gauntlet. He let it be known that from now, you either stand with Raphael or you stand with him.
"And so went the long road of good intentions."
Powers/Skills:
Even low ranking angels in Supernatural are insanely powerful, so Castiel like his angel buddies already here will also have to be powered down. The basic bits are as follows:
• Teleportation: So long as an area is not guarded by angel warding sigils, Castiel can instantly teleport anywhere.
• Angelic Endurance/Strength: He is able to take quite a few hard hits without dying (as in, stabbings and shotgun shells to the chest don't really slow him down) and also possesses strength beyond that of the strongest human. Castiel can do things like throw people around no problem, push around furniture with a simple push of one hand, and survive falling out of a fourth story window and crushing the car he lands on without more than a scratch.
• Supernatural Perception: Such as being able to see ghosts and reapers, seeing the true face of demons and angels, and being able to tell if someone is some form of supernatural creature or human.
• Some Touch Based Skills such as Induced Sedation where simply a touch to the forehead can cause a person to temporarily lose consciousness and Healing of even the worst injuries. (Though for the purpose of the roleplay, these can be totally watered down to just being able to heal some cuts or make a person dizzy or something if necessary.)
He is also proficient in hand to hand combat and knife fighting, so even without his powers he should be able to hold his own in a fight.