Plot Armor?

The basic premise of this system of resurrection is that you want player death to have immediate consequences: Not being able to complete a mission or delaying the players long enough so that way the villain can complete the ritual.

But you don't want them to have long-term consequences: Not being able to play your character. Having to go on lengthy multi-session quests to find someone willing and able to cast the correct spell to bring you back can be fun, but after a few times, it can get old.

So in order to achieve the former and avoid the latter, it's recommended that you bake the reason for the players coming back from the dead into the story. Death still matters or course, after all the players will have allies (:<

If your players aren't too attached to their characters, then who needs plot armor? Let 'em die. If they are, consider some of the options below.