Sorry this took so long, not that anyone seems to read this but anyway. I'm aware this is quite short, however there will be more to come!
No doubt you believe you know what happens, and I wish I could tell you it was true and all that easy but, like many things on this god forsaken earth what happened was so unbelievably complex and heart-breaking and human. Kind of ironic, a human meeting between a fallen angel and a risen demon; sounds like one of those jokes John loves and I don't understand. Real supernatural creatures don't bargain with death, death is just a means to an end. We bargain in knowledge, in secrets, in scandals that could unveil us and humiliate us. We bargain with dreams and fears and with our souls. Our bodies mean nothing; they are purely transport so as long as our soul is intact we can get new transport. It's painful and difficult changing form but it is possible, easier for demons as they don't have wings that don't fit in a human body but as I cut mine off I don't really have that problem.
Some of what you know is correct, we met on that roof top and Moriarty monologued at me for who knows how long and he did destroy himself. That was a strange moment, meeting a demon who understood the pain in staying alive while everyone are you died. Maybe Moriarty was right, we did understand each other too well. However what you may now know is that I didn't 'die'.
For an angel falling is one of the most fearful things imaginable. I can still remember the feel of my wing muscles struggling to stop the fall with no avail. The memories it raises of the fall from heaven would cause a lesser being to collapse even before the landing. That old saying 'falling is just flying with a more permanent destination', while true in essence is very much in correct. Flying is one of the few things I miss from before I cut off my wings, the pure elation and fatigue it causes is very hard to mimic. The closest I've got since was probably when in bed with John, maybe humans have the right idea there.