AN: This is pretty blasphemous, I think. This idea came to me out of the blue one day, and I just had to write it down before it drove me insane. If alternate interpretation of religion offends you, please don't read. Supernatural and it's characters belong to Kripke et al.
Castiel was feeling most perturbed. He had followed his Lord's instructions, but the Winchester boy appeared most unsuitable. He'd been sure that Dean would be able to see his true form, but that wasn't the case. It seemed his time in Hell had more effects than the angels had expected.
Castiel thought back to the time when their Lord had made His momentous decision. He along with the other angels, had thought He'd settled in, accepted His role among them as the leader of the Assembly, guardians of the world.
Joshua, as He'd preferred to be called among the humans, had been confused at first. Understandable. The transition from Earth to the higher plane of Above, to be among the purified forms of the Angels would be difficult for one unfamiliar with them, no matter how enlightened he'd been in life.
His feeling for the people suffering on earth never faded. He still felt so strongly, and had wished to walk amongst once again. But the angels had persuaded Him to stay with them, and help them in devising subtle ways to guide them to the Right.
And the angels were happy. At least they had someone to bring new ideas, and act as mediator and tiebreaker when they weren't able to agree.
Until Then. Joshua had been restless, but not one of the Winged foresaw what He did that day.
He opened the Door. And He had said unto all his angels, "I need to be there with them. I can do much more good that way. Should you need me, you will be able to find me easily."
And so they let Him go.
The angels missed Him, but they did their duty and waited and watched. Mankind grew and developed, fought and reconciled. There had been a few times when they thought they might have to find Him again, but fortunately, things worked out and history flowed on.
Until Azazel was killed. All of them felt it – a Fallen was still an angel, after all.
They thought things would settle down, but somehow, a Gate was opened and many devils were released.
As was Lilith. So they watched closely. The humans made some progress, but they were losing.
Almost every angel in the Assembly was dispatched to search for him. Castiel himself took the area now know as America.
There were several spots of power, including a rather bright one that was almost familiar and intent on banishing the darkness of the escaped demons.
But He wasn't there.
Meeting once again with the others, none of them had been able to find Him either. It was impossible! If He wasn't Above, and not on Earth where he'd promised to be, then…
Castiel was the first to realize it, and vanished while the others were arguing, before they realized the truth.
Forcing his way into Hell was fairly easy. The demons circled and hissed, but dissolved like smoke if they came near. Finding Him was hardly difficult – he had the brightest soul in the horrible place, though it seemed dimmed, torn and bleeding in places. He grasped Him and pulled Him out.
But when he tried to speak to Him, he could not. It was unthinkable! But it had also been unthinkable that He would end up in Hell in the first place. So they would be patient. Perhaps He still needed to recover from the trauma.
It was so strange that in this incarnation, He would be so reluctant to believe in them, in their task. Obviously Castiel couldn't tell him of his true identity at once, who knows what might happen.
And so he settled in to watch and wait. Unsurprisingly, Dean's brother Sam was the bright spot that he'd felt before, though it felt a bit…shadowed. It was as expected – He had always been drawn to the eddies of power found in history, towards the people that would make a difference. He would burn away the shadows surrounding them, and save them all.