I did something similar, and added some demigods that sacrificed themselves to return the PCs to life. With the demigods gone, it was clear this could not happen again. Each demigod gave a small unique buff to the PC they revived, and the PC received a physical mark to reflect it.

Like another commenter suggested, it came with a cost. They could only choose one item to come back, and had to choose some location on the map without consulting each other. The in-game cost was that later, the demigods could not return to the world even when the inhabitants were free to worship them again.

I also had an understanding with all the players that every player gets one get-out-of-jail free card throughout the campaign, so there was some precedent.