You reignite the fires of youth within a willing creature you touch, restoring it to its ultimate glory. Its body, mind, and soul are reverted to the prime of its life, and any nonmagical poison or disease affecting it is removed, as are all levels of exhaustion. It is also immune to magical effects that would increase its age.   Despite its youthful vigor, the target’s natural lifespan remains unchanged.   The first time the creature is reduced to 0 hit points, it remains conscious and its body is engulfed in harmless flames. For the next hour, the target can act normally, is immune to all damage, and does not have to make death saving throws.   After the hour ends, the target dies, and its body is reduced to ashes, and it cannot be restored to life by any means short of a wish spell. No magic or effect can prevent this death and the destruction of its body, even if the spell ends early.