Rune
Once A Fool
Since your players are concerned with story, I would make the cost for returning to life part of the narrative and separate it from mechanics completely.
When someone dies that's when the Devil shows up to make a deal with the survivors to bring their dead companion back to life. Or the party's wizard friend has a new spell he created that should bring the dead back to life. Or as the party is bringing their companion's body to their family for burial, miraculously the person comes back to life.
This is great, but to put it more generally, anyone that your PCs end up owing a favor to is an instant plot-hook. The really fun part is making it as hard a choice as possible whether it's worth bringing a PC back, or not.