undeath

noun

1. (uncountable)The state of being undead.

   “After the vampire bit me, I passed from life to undeath.”

2. (uncountable)The moment of passing into an undead state.

   “"That invitation was made before your death. Or undeath. Or whatever you call it." "Rebirth," he whispered. "Begone!"”

   “No one could decide for certain whether the specimen as a whole were alive or dead, only that some organ function remained and the cells continued to regenerate, albeit at a much slower rate than before their death. Or undeath.”