Do effects that prevent someone from becoming an undead stop the creature from becoming undead, or merely delay it?
For example, if a character is killed by a vampire's bite, but then hit with a gentle repose spell or a similar spell before being buried, does the spell prevent them from becoming a spawn? Or does it only delay them becoming a spawn for the duration?
Best Answer
The humanoid is protected
The bite creates undead the following night after ground burial
The bite of a vampire (MM, 352) states (my emphasis):
A vampire spawn (MM, 354) is classified as:
So, should the humanoid be buried after a bite, they would rise the following night as an undead.
Gentle repose prevents that
This is where gentle repose (PHB, 245) comes in:
In this case, the effects of the vampire bite are RAW completely prevented. Since the Vampire bite's text specifically states that they will become a spawn on the following night, if that night they are protected, then they have passed the gate and are no longer at risk. The fact that the spell continues longer doesn't really change anything as the first night gate has passed and the corpse will not rise as undead after that.