Quote Originally Posted by zergling.exe View Post
I believe it was either detailed in a splat, or is something specific to perhaps demons/devils. But there is something that says that at least some outsiders are pretty much incapable of being killed, as they always reform on their home plane at some point in the future.
It actually is detailed in the summoning section.

Summoning
A summoning spell instantly brings a creature or object to a place you designate. When the spell ends or is dispelled, a summoned creature is instantly sent back to where it came from, but a summoned object is not sent back unless the spell description specifically indicates this. A summoned creature also goes away if it is killed or if its hit points drop to 0 or lower. It is not really dead. It takes 24 hours for the creature to reform, during which time it can’t be summoned again.

But as I pointed out that's not the case because a calling spell is being used, then that was refutted by saying it was an inherent thing of outsiders. I flatly said no to that.