Aziraphale has participated in prisoner exchanges before. There have been a few over the centuries – demons getting careless, angels not knowing the correct earthly protocols, a slip here, an accident there. It's usually all rather a lot of fuss over nothing – neither side really wants to deal with prisoners of the other. A token attempt is always made to extract whatever information they can reasonably be expected to have – none, in essence – but imprisoning an enemy agent for any length of time leads to unnecessary friction and is generally regarded as too much hassle for too little reward.
That is, in the case of most earthly agents. The serpent of Eden, on the other hand, is a different matter. A reputation is a terrible thing to have sometimes. It is the reason Crowley is the only one standing on Heaven's side of the floor, and why there is a string of malnourished looking angels on Hell's. It is the reason Heaven's exchange officers look, in Aziraphale's opinion, rather smug and unjustifiably proud of themselves.
It doesn't explain the nervous attitudes of the demons facilitating the exchange – in Aziraphale's previous experience, they usually jeered right back regardless of which side originally initiated the transfer, and if that had been themselves they directed those jeers at the captives instead for getting caught in the first place – or the looks Crowley keeps darting around. It had given Aziraphale a fright to see him without his sunglasses, marched between Sandalphon and Uriel – Sandalphon was a frequent presence at such transfers, although not usually in an official capacity, but Uriel was not.
Aziraphale doubts he himself would get an escort of any dukes or princes of Hell were his and Crowley's roles reversed.
"Seven lost little angels for one misplaced snake," one of the demons spits. "There. Hand 'im over."
"Do you know, I think we could have asked for more for him?" Uriel says mildly, glancing at Aziraphale. "How unexpected – you were right, Aziraphale, perhaps we did underestimate his value to the other side."
Aziraphale winces minutely. There had been talk of keeping Crowley – murmurs that surely he would know more than some human-possessing nobody, arguments over his relative value to Hell, Sandalphon looking worryingly excited – and he'd argued strenuously that in the end keeping Crowley of all demons came with the exact same drawbacks of any Hellish agent and a few more besides and wouldn't it best to strike while the iron was hot and simply see how many of their own could be returned to Heaven's fold for the sake of single demon?
Seven, as it turns out. Aziraphale hadn't known Hell had that many. Or that they could still have more, if Uriel's implication is correct. The last capture he remembers hearing about was in the early twentieth century.
"The snake," the demon snaps, glancing over their shoulder, gesturing impatiently. Uriel takes their time unlocking Crowley's restraints and the longer they take the more nervous – frightened the demons are. Aziraphale lets his eyes flicker to Crowley, careful not to linger, just long enough to take in the way he rubs at his wrists where the restraints have chafed – no, burned, they've burned him. Of course they have, they're Divine, they have to be to actually restrain a demon. It doesn't look that bad, all things considered – like a vicious sunburn on a human, perhaps – it's just... it's never bothered Aziraphale before.
"Walk, demon," Sandalphon says, and helps Crowley along by way of a quick shove, sending him a few stumbling steps forward before he can regain his balance. Aziraphale curls his hands in his coat pockets and watches Crowley do his best pretense of a saunter as he makes his way across the empty space. It should fool just about everyone else, but his eyes are golden yellow without any whites, meaning he is afraid or stressed or furious, and Aziraphale hates all of those options. He passes the angels he has been exchanged for without a hitch in his step, his shoulders getting tighter the closer he gets to his own lines.
Heaven goes for re-education with their agents but how Hell deals with any of their people unfortunate enough to be captured Aziraphale doesn't know and has never wanted to find out.
He bites his lip when Crowley slips suddenly from one shape to another – Crowley always prefers his human shape, never takes his first one without reason. He claims it's because he's worried he'll forget how to change back but Aziraphale has always had his doubts –
Aziraphale feels faint.
Crowley rears up briefly, then glides towards the deep shadows behind his petrified exchange officers, to the presence there that Aziraphale can't believe he didn't notice before – it's so strong, so malevolent. He glances frantically at Uriel and Sandalphon and is not reassured in the slightest that they look as aghast as he feels.
They love me Downstairs, Crowley told him once, and Aziraphale had laughed into his glass of wine, assuming Crowley was exaggerating, assuming Crowley held much the same status in Hell as Aziraphale did in Heaven – just another agent of the front line, mostly forgotten, diligent with his reports because regular notices of 'all's well' meant no inclination to check further on the part of his superiors. He'd played on Crowley's reputation but he'd thought it was mostly smoke and mirrors, had laughed fondly inside at the idea of Crowley being someone Hell would miss.
Satan's clawed hand reaches out of the shadows to turn Crowley's head this way and that, examining him for injury. WELCOME BACK, CROWLEY. DID YOU HAVE FUN?
Crowley hisses softly as Satan picks him up effortlessly, draping him over his shoulders like – like a scarf, like decoration. Aziraphale realises suddenly that he is surrounded by his fellow angels, that everyone on Heaven's side of the room has drawn together in their fear, from archangels to newly released prisoners, staring across at the shadowed figure of the Adversary.
The Adversary, and the snake whispering in his ear of where Heaven keeps its prisoners and what defences he noticed there as if he'd planned on being captured from the start.