[Sarinpa1]

dullahans being a form of undeath likely stems from hugglord or some aspect of him.

Forgot to mention, Dullahan and Lich scale sanctity like the bujeezus but are perfectly godless. Hell, Lich specifically states they shut out gods.

Edit: mentioning this because people are going to complain that sanctity has to do with gods and nothing else while this is obviously not the case.

sanctity
[sangk-ti-tee]

noun, plural sanctities.
1.
holiness, saintliness, or godliness.
2.
sacred or hallowed character:
the inviolable sanctity of the temple.
3.
a sacred thing.