Q: Can you kill a Demon’s host body with a Death Note?
A: This one is tricky. Deathnote assumes the existence of the supernatural whereas Demon is very materialist in its world view. So I’m not even sure how these two characters could even exist in the same universe. I suppose it comes down to whom the deathnote is actually killing, Jimmy or his current host’s body. Personally, I would feel that the deathnote acts upon one’s body, not their flastical or “soul”. For example, if the cause of death is not specified, the deathnote gives its victim a heart-attack. But as Jimmy’s heart already stopped beating 10 issues ago, I’m not sure writing the name “Jimmy Yee” would actually do anything. Writing “Lee Marsh” while Jimmy is possessing him might work to stop Lee Marsh’s heart but then Jimmy would just transfer on to his next host. All this is to say if Light Yagami and Jimmy Yee got into a fight, I think Jimmy would win.