I enjoyed the story on the whole, it was an interesting concept and I liked your take on Dean and the power of his strength. It felt believable the way he dealt with his pain and the situation he found himself in. Sam seemed in character as well for how he dealt with Dean getting taken. As for Jo can't say much about her. I've never really went much for Jo/Dean.

The angels were interesting and I enjoyed their similarities to the Winchester dynamics. I hope to see them developed further in the next story. 

On that note there are some things that I found a little unbelievable, and yes I know that sounds weird considering the genre, but how did Micheal commander of Gods Army, winner against the devil himself become possesed by a demon? Even a high ranking one, when he managed to defeat the original fallen angels? This I can write off as artistic license and suspend my disbelief but it might be something to address in the sequel.

Also with the amount of injuries Dean sustained I think Sam would have taken him to the hospital. I did like the brotherly togetherness in the final chapter but you could have achieved the same feel with a hospital scene.  I'm not sure where this was placed in the supernatural seasons but wanted by the FBI or not I don't think Sam would have risked  treating injuries this severe. I know that you said some of his injuries were healed but on reading the final chapter it sounded like Dean was only healed enough to stop him from ending up dead and nothing more. A hospital trip would have been upsetting to Dean but if his shoulder really was shattered and there were bone fragments, he would have needed surgery to remove the fragments, before putting it back into place. Sam should have also been worried about shock setting in due to blood loss, not to mention infection. All things considered I think Sam would have hauled his brother to the nearest ER rather than to a motel, even considering the story Sam would have had to make up to explain the injuries.

Thank you for the interesting read and I look forward to seeing what the Winchesters brothers are up to in your other stories.