Free Associated by Neel Krishnaswami; Tweaked by the TLE

There is a notion that human souls who are dead but not in Heaven or Hell damage the machinery of reincarnation, thus damaging the Symphony as a whole. No one soul hurts that much, but when the numbers start climbing into the tens or hundreds of millions Eli and Israfel get that twitchy look and the other angels decide Steps Must be Taken, especially because that's a sign that Gabriel will soon start getting twitchy and she's just a disaster waiting to happen...

This lets the GM do all sorts of complicated political things as the Ethereals jockey with the Host and the Exiles to make sure it's that other pantheon gets the Hammer of Eit come down upon them.

Plus, it gives Sorcerers a lever to bootstrap themselves into much more commanding positions with regard to ethereal gods, since an ethereal summoned and bound into a jar is likely to get overlooked when the hordes of black-winged Malakim are strafing the shining boulevards of Olympus with Holy Machine Gun fire. (And it's a nice excuse for vengeful survivors of the massacres that are perpetrated, and for angels to feel all guilty and angstful about vaporizing an otherwise innocent set of gods just because the universe would die if they didn't.)

Knowledge of which pantheon is to be next on the hit list is quite likely extremely valuable information. Enough to kill for. Or base an adventure around. This also makes it important to have just enough worshippers to survive disaster but not so many that the angels decide that they can reboot the reincarnator by wiping out just your pantheon.

So now we have an excuse why there are all these extinct pantheons are still hanging around - free agency. IOW, if an ethereal pantheon starts collecting too many worshippers it makes sense to trade the souls of the dead to other ethereals so that they can stay alive and remain tempting targets for the angels.

This means that there's a slave trade in the souls of the dead. That's good. It gives Abel and his bunch of murderous revolutionaries another thing to be pissed off at, and something else for Blandine and Beleth to do. And, a location, with a good poem to back it up; a place for the PCs to go buy stuff when they need things that Marc won't - quite - countenance being sold in his bazaar: The Goblin Market.