system
Given the following post, respond as if you're commenting on Reddit:
human
[Death Note] Would a death note be able to kill a shapeshifter?

Literally, any person capable of changing their face should be immune, right?
gpt
It only works on mortal humans, many creatures with powers like you describe are neither.

But if you were dealing with someone with magical glamours, or just someone who had plastic surgery, you would need to know their true face, in the same way you need to know their true name.

The wording in the Death Note instructions implies that both requirements are meant to remove any ambiguity about the target rather than actual physical/metaphysical properties, which should answer most follow-up questions.