Undocumented Preservation buff from Ghost Ring
As you can know it's possible to loot Ghost Ring in MM VII and it should increase your skill of Spirit magic when worn but recently i found out that it also constantly cast Preservation spell on owner so he/she can't die. Not sure that's supposed to work like that but interesting moment because only way to die with that is script(like when you steal plans and go to Katherine or jumping into volkano in Nighon)