I can't seem to find any rule anywhere that clearly states what happens when an eidolon is killed.
Do they unmanifest at 0 hit points? Do they leave a corpse on the field that can go to dying 4 and need to be resurrected?
What exactly becomes of them when they drop in combat and are killed outright?
EDIT: Seems I was confused. The rules say what happens when YOU run out of hit points, but not when your eidolon runs out of hit points. Thing is, that's the same thing. When you're eidolon runs out of hit points, you do too, and your eidolon unmanifests.
So what happens when you manifest them again? They just return at whatever hit points that you currently have? I guess that they do.
Though I get it now, I feel it could have been written a little more clearly. Feels like I had to jump through a couple hoops to get there.