Ok.....
Little problem with demon theory......
we allow a summoned demon to be paid in addition to the mastery spells generally in gold or favors. This means the demon needs to be able to take stuff back to wherever with him when he leaves after the task is done. So our demons can have pouches and such or they need to swallow the gold.
Anyway, if a Demon is killed with a NONslaying arrow through the eye the Demon dissipates and returns to their home plane where they are NOT dead just exhausted. ( since other rules say they need X number of days to recuperate before being resummoned) So the arrow goes with the Demon.
The question has arisen, if th3e demon has organs and such not just goo, then is he healed in the planer translation for a cost to their health or what?