User blog comment:Rei Furuya/Death of a Demon/@comment-36009152-20181110160933/@comment-32952945-20181110202150

Interesting, then I guess slaying Vampires would be impossible and humanity will be in danger. For example if one's to be killed (excluding unknown demons who were once in the Moon Demon Company and died) they would lie helpless and vampires would reign over.

Demons have their own free will in the host mind body, lets put it as if the host (example: Yu) were to die what will happen to the demon in the sword? I wonder if Asuramaru would be stuck in sword form forever since bonding with the host is the only thing keeping him intact.

It's true Demons Cursed Gear swords are important for human survivalibilty but if one were to be killed they could probably disappear to an unknown space or whatever place it could be.